Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 3 5 0 7 2 7 6 8 0 5 *
0478/11
COMPUTER SCIENCE
Paper 1 Theory
May/June 2016
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 13 printed pages and 3 blank pages.
DC (NF/CGW) 119032/4
© UCLES 2016
[Turn over
2
1
Some software can be described as free, freeware or shareware.
Tick (✓) the appropriate boxes in the table below to show which features apply to these three
types of software.
Software feature
Free
Freeware
Shareware
Software source code can be freely accessed and
modified as required
All the features of the full version of the software
are not made available; the full version needs to be
purchased first
The original software is subject to all copyright laws
It is possible to distribute modified versions or
copies of the software to friends and family
[3]
2
Hexadecimal codes are used in MAC addresses.
(a) State what is meant by the term MAC.
...............................................................................................................................................[1]
(b) Explain what the hexadecimal code in a MAC address represents.
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3
3
(a) Five sensors and five applications are shown below.
Draw a line to link each sensor to its most appropriate application.
Sensor
Application
Light
sensor
Monitor the pollution levels in a river
Moisture
sensor
Control the switching off and on of
street lights
Gas
sensor
Detect intruders breaking into a
building
pH
sensor
Monitor the amount of water left in
clothes in a dryer
Pressure
sensor
Monitor acidity levels in the soil in a
greenhouse
[4]
(b) Automatic doors in a building are controlled by the use of infrared sensors and a
microprocessor.
Describe how the sensors and the microprocessor are used to automatically open a door as
a person approaches.
...................................................................................................................................................
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4
4
(a) Nikita wishes to print out some documents and connects her printer to the computer using
one of the USB ports.
(i)
Identify what type of data transmission is being used.
.......................................................................................................................................[1]
(ii)
Give three reasons for using a USB port.
1 .......................................................................................................................................
...........................................................................................................................................
2 .......................................................................................................................................
...........................................................................................................................................
3 .......................................................................................................................................
...........................................................................................................................................
[3]
(iii)
The printer runs out of paper while it is printing the documents. A signal is sent to the
processor to request that the problem is dealt with.
Name this type of signal.
.......................................................................................................................................[1]
(b) State one suitable application for each printer below. A different application must be given for
each printer.
Inkjet printer ..............................................................................................................................
...................................................................................................................................................
3D printer ..................................................................................................................................
...................................................................................................................................................
[2]
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5
(c) Name another type of printer and describe one way in which it is different from the printers
named in part (b).
Give an application for this printer.
Type of printer ...........................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Application ................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2016
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6
5
A computer-controlled machine produces plastic sheets. The thickness of each sheet must be
within a certain tolerance. The sheets are kept below 50 °C as they move over rollers at 10 metres
per second.
Three parameters need to be monitored all the time.
Parameter
D
S
T
Description
Binary
value
Conditions
1
thickness of sheet in tolerance
0
thickness of sheet out of tolerance
1
roller speed = 10 metres/second
0
roller speed <> 10 metres/second
1
temperature < 50 °C
0
temperature >= 50 °C
sheet thickness
roller speed
temperature
An alarm, X, will sound if:
thickness is in tolerance AND (roller speed <> 10 metres/second OR temperature >= 50 °C)
OR
roller speed = 10 metres/second AND temperature >= 50 °C
(a) Draw a logic circuit to represent the above monitoring system.
D
S
X
T
[6]
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7
(b) Complete the truth table for the monitoring system.
D
S
T
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working Space
X
[4]
6
Secure socket layer (SSL) is used in the security of information on Internet websites.
(a) State how it is possible for a user to know that a website is secure by looking at the web
address.
...................................................................................................................................................
...............................................................................................................................................[1]
(b) Describe three of the stages a web browser goes through to detect whether a website is
secure.
1 ...............................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ...............................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
3 ...............................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2016
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8
7
Each seat on a flight is uniquely identified on an LCD above the seat. For example, seat 035C is
shown as:
The first three characters are digits that represent the row.
The fourth character is the seat position in that row. This is a single letter, A to F, that is stored as a
hexadecimal value.
Each of the four display characters can be stored in a 4-bit register. For example, 0 and C would
be represented as:
0:
C:
8
4
2
1
0
1
0
1
0
0
0
0
(a) Show how the 4-bit registers would store the remaining two characters, 3 and 5.
3
5
[2]
(b) Identify which seat is stored in the following 4-bit registers.
0
0
0
1
1
0
0
1
0
1
0
0
1
1
1
0
[2]
© UCLES 2016
0478/11/M/J/16
9
8
A bank offers an online service to its customers. The bank has developed a “SafeToUse” system
that asks each customer to enter four randomly chosen characters from their password each time
they log in.
The customer selects these four characters from drop-down boxes. For example:
Please select the
2nd character
5th character
6th character
8th character
(a) (i)
Explain why it is more secure to use drop-down boxes rather than entering characters
using a keyboard.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(ii)
Give a reason why the system asks for four characters chosen at random.
...........................................................................................................................................
.......................................................................................................................................[1]
(b) Biometrics is an additional form of security.
Give two examples of biometrics.
1 ...............................................................................................................................................
2 ...............................................................................................................................................
[2]
© UCLES 2016
0478/11/M/J/16
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10
9
Check digits are used to ensure the accuracy of entered data.
A 7-digit number has an extra digit on the right, called the check digit.
digit position:
1
2
3
4
5
6
7
8
digit:
–
–
–
–
–
–
–
–
check digit
The check digit is calculated as follows:
•
•
•
•
each digit in the number is multiplied by its digit position
the seven results are then added together
this total is divided by 11
the remainder gives the check digit (if the remainder = 10, the check digit is X)
(a) Calculate the check digit for the following number. Show all your working.
4
2
4
1
5
0
8
…
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Check digit ................................................................................................................................
[2]
(b) An operator has just keyed in the following number:
3
2
4
0
0
4
5
X
Circle below correct if the check digit is correct OR incorrect if the check digit is incorrect.
correct
incorrect
Explain your answer.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2016
0478/11/M/J/16
11
10 Six security issues and six descriptions are shown below.
Draw a line to link each security issue to its correct description.
Security issue
Description
Pharming
illegal access to a computer system
without the owner’s consent or
knowledge
Phishing
software that gathers information by
monitoring key presses on a user’s
keyboard; the data is sent back to the
originator of the software
Viruses
malicious code installed on the hard
drive of a user’s computer or on a web
server; this code will re-direct the user
to a fake website without the user’s
knowledge
Hacking
creator of code sends out a
legitimate-looking email in the hope
of gathering personal and financial
information from the recipient; it
requires the user to click on the link in
the email or attachment
Spyware
a message given to a web browser by
a web server; it is stored in a text file;
the message is then sent back to the
server each time the browser requests
a page from the server
Cookies
program or code that replicates itself;
designed to amend, delete or copy
data or files on a user’s computer;
often causes the computer to crash or
run slowly
[5]
© UCLES 2016
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12
11 (a) Four examples of optical storage media are:
•
•
•
•
DVD-RW
DVD-RAM
CD-ROM
Blu-ray disc
The table below shows four features of optical storage media.
Tick (✓) the appropriate boxes in the table to indicate which of the features apply to each
example of optical storage media.
Single track
Many
concentric
tracks
Blue laser
used to read/
write data
Red laser
used to read/
write data
DVD-RW
DVD-RAM
CD-ROM
Blu-ray disc
[4]
(b) Solid state drives (SSD) are replacing hard disc drives (HDD) in some computers.
(i)
Give three reasons why this is happening.
1 .......................................................................................................................................
...........................................................................................................................................
2 .......................................................................................................................................
...........................................................................................................................................
3 .......................................................................................................................................
...........................................................................................................................................
[3]
(ii)
Explain why many web servers still use hard disc drive (HDD) technology.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
© UCLES 2016
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13
12 (a) Name the following type of barcode:
...............................................................................................................................................[1]
(b) The barcode in part (a) contains the denary value
2640
Convert this value to hexadecimal.
...................................................................................................................................................
...................................................................................................................................................
Write the value as a 12-bit binary number.
[4]
(c) An airport uses the type of barcode shown in part (a) to advertise local places of interest.
Describe how a visitor landing at the airport could use these barcodes to help plan their visit.
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© UCLES 2016
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© UCLES 2016
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable
effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will
be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2016
0478/11/M/J/16
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
May/June 2016
Paper 1
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2016 series for most Cambridge IGCSE®,
Cambridge International A and AS Level components and some Cambridge O Level components.
® IGCSE is the registered trademark of Cambridge International Examinations.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 10 printed pages.
© UCLES 2016
[Turn over
Page 2
1
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
11
1 mark for each correct column
Software feature
Free
Software source code can be freely accessed
and modified as required
Freeware
All the features of the full version of the software
are not made available; the full version needs to
be purchased first
The original software is subject to all of the
copyright laws
It is possible to distribute modified versions or
copies of the software to friends and family
Shareware
(1 mark)
(1 mark)
(1 mark)
[3]
2
(a) media access control
[1]
(b) Any three from:
–
–
–
–
–
hardware/physical address
unique address/number associated (with network card in) a device/computer
usually 48/64 bits (12/16 hex digits)
first 6/8 digits = manufacturer code/ID of device (NIC)
last 6/8 digits = serial number of device (NIC)
© Cambridge International Examinations 2016
[3]
Page 3
3
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
11
(a)
Light
sensor
Monitoring the pollution levels in a river
Moisture
sensor
Control the switching off and on of
street lighting
Gas
sensor
Detection of intruders breaking into a
building
pH
sensor
Monitor the amount of water left in
clothes in a drier
Pressure
sensor
Monitor acidity levels in the soil in a
greenhouse
4/5 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
[4]
(b) Any four from:
–
–
–
–
–
–
sensor(s) sends signal/data to microprocessor
signal/data converted to digital (using an ADC)
microprocessor compares signal/data with pre-set/stored value
if sensor(s) signal/data indicates the presence of a person / the door needs to be opened
/ a match is found / door is closed …
… microprocessor sends a signal to an actuator …
… to operate/drive a motor to open the door
[4]
© Cambridge International Examinations 2016
Page 4
4
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
(a) (i) serial
Paper
11
[1]
(ii) Any three from:
– automatically detects the hardware/installs drivers
– plug only goes in one way/can’t connect incorrectly
– supports different data transmission speeds/a range of data transmission speeds
– has become the industry standard/universally used
– backwards compatible (with earlier versions of USB ports)
[3]
(iii) interrupt
[1]
(b) 1 mark each use of printer, max 1 mark per printer.
inkjet printer
– (small quantities of) documents
– photographs
3D printer
– (physical) prototype (from CAD)
– (physical) model (from a blueprint)
[2]
(c) 1 mark for naming printer + 1 mark for description + 1 mark for application
Laser printer
–
–
–
–
–
–
–
uses toner/powder ink
uses (positive and negative) charged drums // rotating drum
uses static charge
no moving head
faster at printing
high volume output/high speed
producing flyers/leaflets/magazines
This is an example, other types of printers can be credited.
© Cambridge International Examinations 2016
[3]
Page 5
5
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
11
(a) 1 mark for each correct gate, with correct source of input(s)
[6]
(b)
D
S
T
Working Space
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
4 marks for 8 correct X bits
3 marks for 6 correct X bits
2 marks for 4 correct X bits
1 mark for 2 correct X bits
© Cambridge International Examinations 2016
X
[4]
Page 6
6
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
11
(a) Any one from:
–
–
protocol ends in “s”
use of https
[1]
(b) Any three from:
–
–
–
–
–
–
7
requests web server to identify itself/view the (SSL) certificate
receives a copy of the (SSL) certificate, sent from the webserver
checks if SSL certificate is authentic/trustworthy
sends signal back to webserver that the certificate is authentic/trustworthy
starts to transmit data once connection is established as secure
if website is not secure browser will display an open padlock/warning message
[3]
(a) 1 mark for each correct binary value
3
0
0
1
1
5
0
1
0
1
[2]
(b)
0
0
0
1
1
1
0
0
1
9
0
1
0
0
4
1
1
1
0
E
1 mark
1 mark
[2]
© Cambridge International Examinations 2016
Page 7
8
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
11
(a) (i) Any two from:
–
–
–
–
–
to protect against key logging software/spyware
can stop key presses being recorded
can stop key presses being relayed
drop down boxes cannot be recorded as key presses
drop down boxes can be placed in different location on the screen each time
(to overcome screen capture issues)
[2]
(ii) Any one from:
–
–
–
–
hacker never finds all characters on the first hack
makes it more difficult for hackers to find the order of the characters
hacker needs to hack the system several times to gain the whole password
shoulder surfing will not give person full password
[1]
(b) Any two from:
–
–
–
–
9
fingerprint scanner
face recognition software
retina scanner/iris scanner
voice recognition software
[2]
(a) 1 mark for correct check digit and 1 mark for showing the calculation
(4 × 1) + (2 × 2) + (4 × 3) + (1 × 4) + (5 × 5) + (0 × 6) + (8 × 7)
= 4 + 4 + 12 + 4 + 25 + 0 + 56 = 105
1 mark for any correct
line of working
105/11 = 9 remainder 6
check digit is: 6
[2]
(b) incorrect check digit
[1]
–
–
–
check digit should be 1
(3*1) + (2*2) + (4*3) + (0*4) + (0*5) + (4*6) + (5*7) // 3 + 4 + 12 + 0 + 0 + 24 + 35 //
Total = 78
78/11 gives 7 remainder 1
© Cambridge International Examinations 2016
[2]
Page 8
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
11
10
illegal access to a computer system
without the owner’s consent or
knowledge
Pharming
software that gathers information by
monitoring key presses on a user’s
keyboard; the information is relayed back
to the originator of the software
Phishing
Viruses
malicious code installed on the hard drive
of a user’s computer or on a web server;
this code will re-direct the user to a fake
website without the user’s knowledge
Hacking
creator of code sends out a legitimatelooking email in the hope of gathering
personal and financial information from
the recipient; it requires the user to click
on the link in the email or attachment
a message given to a web browser by a
web server; it is stored in a text file; the
message is then sent back to the server
each time the browser requests a page
from the server
Spyware
program or code that replicates itself
designed to amend, delete or copy data
or files on a user’s computer; often
causes the computer to crash or run
slowly
Cookies
5/6 matches – 5 marks
4 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
© Cambridge International Examinations 2016
[5]
Page 9
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
11
11 (a) 1 mark for each correct row
Single track
Many
concentric
tracks
Blue laser
Red laser
used to read/ used to read/
write data
write data
DVD-RW
DVD-RAM
CD-ROM
Blu-ray disc
1 mark
1 mark
1 mark
1 mark
[4]
(b) (i) Any three from:
–
–
–
–
–
–
–
–
don’t need to “get up to speed” to work properly/no latency
lower/less power consumption/more energy efficient
run cooler
run quieter
data access is faster
occupies less physical space/more compact
lighter, so more suitable for a portable computer/laptop
no moving parts so more reliable/durable in a portable computer/laptop
[3]
(ii) Any two from:
–
–
–
–
HDD is cheaper for larger amounts of storage space
HDD has greater longevity for read/write functions
Expensive to change the technology // HDD are trusted technology
No requirement for the increased speed of SSD
© Cambridge International Examinations 2016
[2]
Page 10
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
12 (a) QR (quick response) Code
(b) –
Paper
11
[1]
A 5 0 (1 mark)
1
0
1
1 mark
0
0
1
0
1
0
0
1 mark
0
0
1 mark
[4]
(c) Any three from:
-
visitor scans the QR code with (the camera on) the mobile device
App is used to read/interpret the QR code
links to a website/opens a document …
… to access local tourist information
can store the QR code to refer to again for the information
© Cambridge International Examinations 2016
[3]
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
May/June 2016
Paper 1
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2016 series for most Cambridge IGCSE®,
Cambridge International A and AS Level components and some Cambridge O Level components.
® IGCSE is the registered trademark of Cambridge International Examinations.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 10 printed pages.
© UCLES 2016
[Turn over
Page 2
1
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
compiler
assembler
interpreter
[3]
2
Application
Sensor
controlling street lights
Light
monitoring a river for pollution
Gas, pH, temperature, light
controlling traffic lights
pressure, magnetic field,
NOTE: The same sensor cannot be given twice
3
[3]
(a) 1 mark for each nibble
0100 1010 1111
(b) (i) 0 1 1 0 1 0 0 1
00011111
00110010
[3]
105 hours
31 minutes
50 seconds
1 mark
1 mark
1 mark
(ii) 1F
[3]
[1]
© Cambridge International Examinations 2016
Page 3
4
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a) Any three from:
– The file can be compressed
– The compression that is used is lossless (not lossy)
– use of a compression algorithm
– repeated words can be indexed
– repeated word sections (e.g. “OU”) can be replaced by a numerical value
– reference to zip files
– save file as a pdf/convert to pdf
[3]
(b) Any four from:
– the checksum for the bytes is calculated
– this value is then transmitted with the block of data
– at the receiving end, the checksum is re-calculated from the block of data received
– the calculated value is then compared to the checksum transmitted
– if they are the same value, then the data was transmitted without any error
– if the values are different, then an error has been found
– if the values are different, then a request is sent for the data to be re-transmitted
[4]
© Cambridge International Examinations 2016
Page 4
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
5
Description
Device
Allows a user to write on a
surface using a pen; text and
drawings are then captured
electronically and stored for
later use.
Digital Light Projector
Converts sound into an
electrical signal/voltage.
Uses thermal bubble and
piezoelectric technology to
produce a hard copy.
Inkjet printer
Interactive whiteboard
Uses a bright white light source
and micro mirrors (on a chip) to
produce an image to be shone
onto a wall or screen.
Converts a hard copy document
into an electronic form to be
stored as a file on a computer.
Uses negatively charged
images on a rotating drum and
positively charged toner to
output a hard copy.
5/6 matches – 5 marks
4 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
© Cambridge International Examinations 2016
Laser printer
Microphone
Scanner (2D)
[5]
Page 5
6
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a)
Type
Tick
()
Method
simplex
serial
half-duplex
parallel
full-duplex
Type
simplex
Tick
()
Tick
()
half-duplex
Method
serial
Tick
()
parallel
full-duplex
Type
Tick
()
simplex
half-duplex
Method
serial
Tick
()
parallel
full-duplex
[6]
(b) Any two from:
– single wire means there is less chance of interference/data corruption
– single wire reduces costs
– more reliable over greater distances
– bits will still be synchronised after transmission
© Cambridge International Examinations 2016
[2]
Page 6
7
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a)
A
B
C
Working space
0
0
0
0
0
0
1
1
0
1
0
0
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
0
4 marks for 8 correct X bits
3 marks for 6 correct X bits
2 marks for 4 correct X bits
1 mark for 2 correct X bits
© Cambridge International Examinations 2016
X
[4]
Page 7
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(b) 1 mark for each correct gate with correct source of input
A
X
B
C
[5]
(c) Each dotted area is 1 mark
A
X
B
C
[4]
© Cambridge International Examinations 2016
Page 8
8
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a) 1 mark for correct lines from each type of software
NOTE: all statements that are correct must be connected to the correct type of
software for the mark to be awarded
Statement
Type of software
Users have the freedom to
pass on the software to
friends and family as they
wish.
Free software
Users can download this
software free of charge, but
they cannot modify the
source code in any way.
Users are allowed to try out
the software for a trial period
only before being charged.
Freeware
Users can study the software
source code and modify it,
where necessary, to meet
their own needs, without
breaking copyright laws.
Shareware
Users can obtain a free trial
version of the software, but
this often does not contain all
the features of the full
version.
[3]
© Cambridge International Examinations 2016
Page 9
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(b) Any three from:
– That we should follow Copyright laws/intellectual property rights/work should not be
stolen/plagiarised
– That we should follow Data Protection laws
– That we should not create or distribute malware//description of malware
– That we should not hack/crack other computers//description of hacking
– That we should protect our own computers against malware/hacking
– That we should consider privacy issues (when using social networking)
– That we consider anonymity issues (when using social networking)
– That we should consider environmental impacts when using computers
– Loss/creation of jobs from use of computers/robotics
– We should follow codes of practice (for creation of code e.g. ACM/IEEE)
[3]
(c) 2 marks for each term described
Viruses:
– program/software/file that replicates (copies) itself
– intends to delete or corrupt files//fill up hard disk space
Pharming:
– malicious code stored on a computer/web server
– redirects user to fake website to steal user data
Spyware:
– monitors and relays user activity e.g. key presses//key logging software
– user activity/key presses can be analysed to find sensitive data e.g. passwords
[6]
(d) Any three from:
– examines/monitors traffic to and from a user’s computer and a network/Internet
– checks whether incoming and outgoing traffic meets a given set of criteria/rules
– firewall blocks/filters traffic that doesn’t meet the criteria/rules
– logs all incoming and outgoing traffic
– can prevent viruses or hackers gaining access
– blocks/filters access to specified IP addresses/websites
– warns users of attempts by software (in their computer) trying to access external data
sources (e.g. updating of software) etc. // warns of attempted unauthorised access to
the system
[3]
© Cambridge International Examinations 2016
Page 10
9
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a)
Binary number A:
1
1
1
0
0
1
0
Binary number B:
1
0
0
1
1
1
0
[2]
(b)
Parity Bit
Binary number A
1
Binary number B
1
[2]
10 1 mark for each correct storage device
ROM (not EPROM/PROM)
Blu-ray disc
RAM
DVD/ DVD-R(+R)/ DVD-RW(+RW)/ DVD-ROM (not CD or DVD-RAM)
SSD/example of a USB storage device
DVD-RAM
[6]
11 1 mark for each correct point
– Presentation is used to format colour/style
– Structure is used to create layout
– In a HTML document structure and presentation are often kept separate
– By keeping the presentation separate it is easier to update colour/font
– Presentation is often stored in a file called a CSS …
– … the CSS in then linked to the HTML document to implement the presentation requirements
– (Mark-up) tags are used to define the structure of the document …
– … presentation and formatting can also be included within the tags
[4]
© Cambridge International Examinations 2016
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
May/June 2016
Paper 1
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2016 series for most Cambridge IGCSE®,
Cambridge International A and AS Level components and some Cambridge O Level components.
® IGCSE is the registered trademark of Cambridge International Examinations.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 10 printed pages.
© UCLES 2016
[Turn over
Page 2
1
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
compiler
assembler
interpreter
[3]
2
Application
Sensor
controlling street lights
Light
monitoring a river for pollution
Gas, pH, temperature, light
controlling traffic lights
pressure, magnetic field,
NOTE: The same sensor cannot be given twice
3
[3]
(a) 1 mark for each nibble
0100 1010 1111
(b) (i) 0 1 1 0 1 0 0 1
00011111
00110010
[3]
105 hours
31 minutes
50 seconds
1 mark
1 mark
1 mark
(ii) 1F
[3]
[1]
© Cambridge International Examinations 2016
Page 3
4
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a) Any three from:
– The file can be compressed
– The compression that is used is lossless (not lossy)
– use of a compression algorithm
– repeated words can be indexed
– repeated word sections (e.g. “OU”) can be replaced by a numerical value
– reference to zip files
– save file as a pdf/convert to pdf
[3]
(b) Any four from:
– the checksum for the bytes is calculated
– this value is then transmitted with the block of data
– at the receiving end, the checksum is re-calculated from the block of data received
– the calculated value is then compared to the checksum transmitted
– if they are the same value, then the data was transmitted without any error
– if the values are different, then an error has been found
– if the values are different, then a request is sent for the data to be re-transmitted
[4]
© Cambridge International Examinations 2016
Page 4
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
5
Description
Device
Allows a user to write on a
surface using a pen; text and
drawings are then captured
electronically and stored for
later use.
Digital Light Projector
Converts sound into an
electrical signal/voltage.
Uses thermal bubble and
piezoelectric technology to
produce a hard copy.
Inkjet printer
Interactive whiteboard
Uses a bright white light source
and micro mirrors (on a chip) to
produce an image to be shone
onto a wall or screen.
Converts a hard copy document
into an electronic form to be
stored as a file on a computer.
Uses negatively charged
images on a rotating drum and
positively charged toner to
output a hard copy.
5/6 matches – 5 marks
4 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
© Cambridge International Examinations 2016
Laser printer
Microphone
Scanner (2D)
[5]
Page 5
6
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a)
Type
Tick
()
Method
simplex
serial
half-duplex
parallel
full-duplex
Type
simplex
Tick
()
Tick
()
half-duplex
Method
serial
Tick
()
parallel
full-duplex
Type
Tick
()
simplex
half-duplex
Method
serial
Tick
()
parallel
full-duplex
[6]
(b) Any two from:
– single wire means there is less chance of interference/data corruption
– single wire reduces costs
– more reliable over greater distances
– bits will still be synchronised after transmission
© Cambridge International Examinations 2016
[2]
Page 6
7
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a)
A
B
C
Working space
0
0
0
0
0
0
1
1
0
1
0
0
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
0
4 marks for 8 correct X bits
3 marks for 6 correct X bits
2 marks for 4 correct X bits
1 mark for 2 correct X bits
© Cambridge International Examinations 2016
X
[4]
Page 7
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(b) 1 mark for each correct gate with correct source of input
A
X
B
C
[5]
(c) Each dotted area is 1 mark
A
X
B
C
[4]
© Cambridge International Examinations 2016
Page 8
8
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a) 1 mark for correct lines from each type of software
NOTE: all statements that are correct must be connected to the correct type of
software for the mark to be awarded
Statement
Type of software
Users have the freedom to
pass on the software to
friends and family as they
wish.
Free software
Users can download this
software free of charge, but
they cannot modify the
source code in any way.
Users are allowed to try out
the software for a trial period
only before being charged.
Freeware
Users can study the software
source code and modify it,
where necessary, to meet
their own needs, without
breaking copyright laws.
Shareware
Users can obtain a free trial
version of the software, but
this often does not contain all
the features of the full
version.
[3]
© Cambridge International Examinations 2016
Page 9
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(b) Any three from:
– That we should follow Copyright laws/intellectual property rights/work should not be
stolen/plagiarised
– That we should follow Data Protection laws
– That we should not create or distribute malware//description of malware
– That we should not hack/crack other computers//description of hacking
– That we should protect our own computers against malware/hacking
– That we should consider privacy issues (when using social networking)
– That we consider anonymity issues (when using social networking)
– That we should consider environmental impacts when using computers
– Loss/creation of jobs from use of computers/robotics
– We should follow codes of practice (for creation of code e.g. ACM/IEEE)
[3]
(c) 2 marks for each term described
Viruses:
– program/software/file that replicates (copies) itself
– intends to delete or corrupt files//fill up hard disk space
Pharming:
– malicious code stored on a computer/web server
– redirects user to fake website to steal user data
Spyware:
– monitors and relays user activity e.g. key presses//key logging software
– user activity/key presses can be analysed to find sensitive data e.g. passwords
[6]
(d) Any three from:
– examines/monitors traffic to and from a user’s computer and a network/Internet
– checks whether incoming and outgoing traffic meets a given set of criteria/rules
– firewall blocks/filters traffic that doesn’t meet the criteria/rules
– logs all incoming and outgoing traffic
– can prevent viruses or hackers gaining access
– blocks/filters access to specified IP addresses/websites
– warns users of attempts by software (in their computer) trying to access external data
sources (e.g. updating of software) etc. // warns of attempted unauthorised access to
the system
[3]
© Cambridge International Examinations 2016
Page 10
9
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
12
(a)
Binary number A:
1
1
1
0
0
1
0
Binary number B:
1
0
0
1
1
1
0
[2]
(b)
Parity Bit
Binary number A
1
Binary number B
1
[2]
10 1 mark for each correct storage device
ROM (not EPROM/PROM)
Blu-ray disc
RAM
DVD/ DVD-R(+R)/ DVD-RW(+RW)/ DVD-ROM (not CD or DVD-RAM)
SSD/example of a USB storage device
DVD-RAM
[6]
11 1 mark for each correct point
– Presentation is used to format colour/style
– Structure is used to create layout
– In a HTML document structure and presentation are often kept separate
– By keeping the presentation separate it is easier to update colour/font
– Presentation is often stored in a file called a CSS …
– … the CSS in then linked to the HTML document to implement the presentation requirements
– (Mark-up) tags are used to define the structure of the document …
– … presentation and formatting can also be included within the tags
[4]
© Cambridge International Examinations 2016
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 0 7 3 3 6 7 4 3 7 5 *
0478/13
COMPUTER SCIENCE
Paper 1 Theory
May/June 2016
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 13 printed pages and 3 blank pages.
DC (ST/CGW) 126906
© UCLES 2016
[Turn over
2
1
Some software can be described as free, freeware or shareware.
Tick (✓) the appropriate boxes in the table below to show which features apply to these three
types of software.
Software feature
Free
Freeware
Shareware
Software source code can be freely accessed and
modified as required
All the features of the full version of the software
are not made available; the full version needs to be
purchased first
The original software is subject to all copyright laws
It is possible to distribute modified versions or
copies of the software to friends and family
[3]
2
Hexadecimal codes are used in MAC addresses.
(a) State what is meant by the term MAC.
...............................................................................................................................................[1]
(b) Explain what the hexadecimal code in a MAC address represents.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
© UCLES 2016
0478/13/M/J/16
3
3
(a) Five sensors and five applications are shown below.
Draw a line to link each sensor to its most appropriate application.
Sensor
Application
Light
sensor
Monitor the pollution levels in a river
Moisture
sensor
Control the switching off and on of
street lights
Gas
sensor
Detect intruders breaking into a
building
pH
sensor
Monitor the amount of water left in
clothes in a dryer
Pressure
sensor
Monitor acidity levels in the soil in a
greenhouse
[4]
(b) Automatic doors in a building are controlled by the use of infrared sensors and a
microprocessor.
Describe how the sensors and the microprocessor are used to automatically open a door as
a person approaches.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
© UCLES 2016
0478/13/M/J/16
[Turn over
4
4
(a) Nikita wishes to print out some documents and connects her printer to the computer using
one of the USB ports.
(i)
Identify what type of data transmission is being used.
.......................................................................................................................................[1]
(ii)
Give three reasons for using a USB port.
1 .......................................................................................................................................
...........................................................................................................................................
2 .......................................................................................................................................
...........................................................................................................................................
3 .......................................................................................................................................
...........................................................................................................................................
[3]
(iii)
The printer runs out of paper while it is printing the documents. A signal is sent to the
processor to request that the problem is dealt with.
Name this type of signal.
.......................................................................................................................................[1]
(b) State one suitable application for each printer below. A different application must be given for
each printer.
Inkjet printer ..............................................................................................................................
...................................................................................................................................................
3D printer ..................................................................................................................................
...................................................................................................................................................
[2]
© UCLES 2016
0478/13/M/J/16
5
(c) Name another type of printer and describe one way in which it is different from the printers
named in part (b).
Give an application for this printer.
Type of printer ...........................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Application ................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2016
0478/13/M/J/16
[Turn over
6
5
A computer-controlled machine produces plastic sheets. The thickness of each sheet must be
within a certain tolerance. The sheets are kept below 50 °C as they move over rollers at 10 metres
per second.
Three parameters need to be monitored all the time.
Parameter
D
S
T
Description
Binary
value
Conditions
1
thickness of sheet in tolerance
0
thickness of sheet out of tolerance
1
roller speed = 10 metres/second
0
roller speed <> 10 metres/second
1
temperature < 50 °C
0
temperature >= 50 °C
sheet thickness
roller speed
temperature
An alarm, X, will sound if:
thickness is in tolerance AND (roller speed <> 10 metres/second OR temperature >= 50 °C)
OR
roller speed = 10 metres/second AND temperature >= 50 °C
(a) Draw a logic circuit to represent the above monitoring system.
D
S
X
T
[6]
© UCLES 2016
0478/13/M/J/16
7
(b) Complete the truth table for the monitoring system.
D
S
T
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working Space
X
[4]
6
Secure socket layer (SSL) is used in the security of information on Internet websites.
(a) State how it is possible for a user to know that a website is secure by looking at the web
address.
...................................................................................................................................................
...............................................................................................................................................[1]
(b) Describe three of the stages a web browser goes through to detect whether a website is
secure.
1 ...............................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ...............................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
3 ...............................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2016
0478/13/M/J/16
[Turn over
8
7
Each seat on a flight is uniquely identified on an LCD above the seat. For example, seat 035C is
shown as:
The first three characters are digits that represent the row.
The fourth character is the seat position in that row. This is a single letter, A to F, that is stored as a
hexadecimal value.
Each of the four display characters can be stored in a 4-bit register. For example, 0 and C would
be represented as:
0:
C:
8
4
2
1
0
1
0
1
0
0
0
0
(a) Show how the 4-bit registers would store the remaining two characters, 3 and 5.
3
5
[2]
(b) Identify which seat is stored in the following 4-bit registers.
0
0
0
1
1
0
0
1
0
1
0
0
1
1
1
0
[2]
© UCLES 2016
0478/13/M/J/16
9
8
A bank offers an online service to its customers. The bank has developed a “SafeToUse” system
that asks each customer to enter four randomly chosen characters from their password each time
they log in.
The customer selects these four characters from drop-down boxes. For example:
Please select the
2nd character
5th character
6th character
8th character
(a) (i)
Explain why it is more secure to use drop-down boxes rather than entering characters
using a keyboard.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(ii)
Give a reason why the system asks for four characters chosen at random.
...........................................................................................................................................
.......................................................................................................................................[1]
(b) Biometrics is an additional form of security.
Give two examples of biometrics.
1 ...............................................................................................................................................
2 ...............................................................................................................................................
[2]
© UCLES 2016
0478/13/M/J/16
[Turn over
10
9
Check digits are used to ensure the accuracy of entered data.
A 7-digit number has an extra digit on the right, called the check digit.
digit position:
1
2
3
4
5
6
7
8
digit:
–
–
–
–
–
–
–
–
check digit
The check digit is calculated as follows:
•
•
•
•
each digit in the number is multiplied by its digit position
the seven results are then added together
this total is divided by 11
the remainder gives the check digit (if the remainder = 10, the check digit is X)
(a) Calculate the check digit for the following number. Show all your working.
4
2
4
1
5
0
8
…
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Check digit ................................................................................................................................
[2]
(b) An operator has just keyed in the following number:
3
2
4
0
0
4
5
X
Circle below correct if the check digit is correct OR incorrect if the check digit is incorrect.
correct
incorrect
Explain your answer.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2016
0478/13/M/J/16
11
10 Six security issues and six descriptions are shown below.
Draw a line to link each security issue to its correct description.
Security issue
Description
Pharming
illegal access to a computer system
without the owner’s consent or
knowledge
Phishing
software that gathers information by
monitoring key presses on a user’s
keyboard; the data is sent back to the
originator of the software
Viruses
malicious code installed on the hard
drive of a user’s computer or on a web
server; this code will re-direct the user
to a fake website without the user’s
knowledge
Hacking
creator of code sends out a
legitimate-looking email in the hope
of gathering personal and financial
information from the recipient; it
requires the user to click on the link in
the email or attachment
Spyware
a message given to a web browser by
a web server; it is stored in a text file;
the message is then sent back to the
server each time the browser requests
a page from the server
Cookies
program or code that replicates itself;
designed to amend, delete or copy
data or files on a user’s computer;
often causes the computer to crash or
run slowly
[5]
© UCLES 2016
0478/13/M/J/16
[Turn over
12
11 (a) Four examples of optical storage media are:
•
•
•
•
DVD-RW
DVD-RAM
CD-ROM
Blu-ray disc
The table below shows four features of optical storage media.
Tick (✓) the appropriate boxes in the table to indicate which of the features apply to each
example of optical storage media.
Single track
Many
concentric
tracks
Blue laser
used to read/
write data
Red laser
used to read/
write data
DVD-RW
DVD-RAM
CD-ROM
Blu-ray disc
[4]
(b) Solid state drives (SSD) are replacing hard disc drives (HDD) in some computers.
(i)
Give three reasons why this is happening.
1 .......................................................................................................................................
...........................................................................................................................................
2 .......................................................................................................................................
...........................................................................................................................................
3 .......................................................................................................................................
...........................................................................................................................................
[3]
(ii)
Explain why many web servers still use hard disc drive (HDD) technology.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
© UCLES 2016
0478/13/M/J/16
13
12 (a) Name the following type of barcode:
...............................................................................................................................................[1]
(b) The barcode in part (a) contains the denary value
2640
Convert this value to hexadecimal.
...................................................................................................................................................
...................................................................................................................................................
Write the value as a 12-bit binary number.
[4]
(c) An airport uses the type of barcode shown in part (a) to advertise local places of interest.
Describe how a visitor landing at the airport could use these barcodes to help plan their visit.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
© UCLES 2016
0478/13/M/J/16
14
BLANK PAGE
© UCLES 2016
0478/13/M/J/16
15
BLANK PAGE
© UCLES 2016
0478/13/M/J/16
16
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable
effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will
be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2016
0478/13/M/J/16
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
May/June 2016
Paper 1
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2016 series for most Cambridge IGCSE®,
Cambridge International A and AS Level components and some Cambridge O Level components.
® IGCSE is the registered trademark of Cambridge International Examinations.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 10 printed pages.
© UCLES 2016
[Turn over
Page 2
1
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
13
1 mark for each correct column
Software feature
Free
Software source code can be freely accessed
and modified as required
Freeware
All the features of the full version of the software
are not made available; the full version needs to
be purchased first
The original software is subject to all of the
copyright laws
It is possible to distribute modified versions or
copies of the software to friends and family
Shareware
(1 mark)
(1 mark)
(1 mark)
[3]
2
(a) media access control
[1]
(b) Any three from:
–
–
–
–
–
hardware/physical address
unique address/number associated (with network card in) a device/computer
usually 48/64 bits (12/16 hex digits)
first 6/8 digits = manufacturer code/ID of device (NIC)
last 6/8 digits = serial number of device (NIC)
© Cambridge International Examinations 2016
[3]
Page 3
3
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
13
(a)
Light
sensor
Monitoring the pollution levels in a river
Moisture
sensor
Control the switching off and on of
street lighting
Gas
sensor
Detection of intruders breaking into a
building
pH
sensor
Monitor the amount of water left in
clothes in a drier
Pressure
sensor
Monitor acidity levels in the soil in a
greenhouse
4/5 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
[4]
(b) Any four from:
–
–
–
–
–
–
sensor(s) sends signal/data to microprocessor
signal/data converted to digital (using an ADC)
microprocessor compares signal/data with pre-set/stored value
if sensor(s) signal/data indicates the presence of a person / the door needs to be opened
/ a match is found / door is closed …
… microprocessor sends a signal to an actuator …
… to operate/drive a motor to open the door
[4]
© Cambridge International Examinations 2016
Page 4
4
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
(a) (i) serial
Paper
13
[1]
(ii) Any three from:
– automatically detects the hardware/installs drivers
– plug only goes in one way/can’t connect incorrectly
– supports different data transmission speeds/a range of data transmission speeds
– has become the industry standard/universally used
– backwards compatible (with earlier versions of USB ports)
[3]
(iii) interrupt
[1]
(b) 1 mark each use of printer, max 1 mark per printer.
inkjet printer
– (small quantities of) documents
– photographs
3D printer
– (physical) prototype (from CAD)
– (physical) model (from a blueprint)
[2]
(c) 1 mark for naming printer + 1 mark for description + 1 mark for application
Laser printer
–
–
–
–
–
–
–
uses toner/powder ink
uses (positive and negative) charged drums // rotating drum
uses static charge
no moving head
faster at printing
high volume output/high speed
producing flyers/leaflets/magazines
This is an example, other types of printers can be credited.
© Cambridge International Examinations 2016
[3]
Page 5
5
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
13
(a) 1 mark for each correct gate, with correct source of input(s)
[6]
(b)
D
S
T
Working Space
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
4 marks for 8 correct X bits
3 marks for 6 correct X bits
2 marks for 4 correct X bits
1 mark for 2 correct X bits
© Cambridge International Examinations 2016
X
[4]
Page 6
6
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
13
(a) Any one from:
–
–
protocol ends in “s”
use of https
[1]
(b) Any three from:
–
–
–
–
–
–
7
requests web server to identify itself/view the (SSL) certificate
receives a copy of the (SSL) certificate, sent from the webserver
checks if SSL certificate is authentic/trustworthy
sends signal back to webserver that the certificate is authentic/trustworthy
starts to transmit data once connection is established as secure
if website is not secure browser will display an open padlock/warning message
[3]
(a) 1 mark for each correct binary value
3
0
0
1
1
5
0
1
0
1
[2]
(b)
0
0
0
1
1
1
0
0
1
9
0
1
0
0
4
1
1
1
0
E
1 mark
1 mark
[2]
© Cambridge International Examinations 2016
Page 7
8
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
13
(a) (i) Any two from:
–
–
–
–
–
to protect against key logging software/spyware
can stop key presses being recorded
can stop key presses being relayed
drop down boxes cannot be recorded as key presses
drop down boxes can be placed in different location on the screen each time
(to overcome screen capture issues)
[2]
(ii) Any one from:
–
–
–
–
hacker never finds all characters on the first hack
makes it more difficult for hackers to find the order of the characters
hacker needs to hack the system several times to gain the whole password
shoulder surfing will not give person full password
[1]
(b) Any two from:
–
–
–
–
9
fingerprint scanner
face recognition software
retina scanner/iris scanner
voice recognition software
[2]
(a) 1 mark for correct check digit and 1 mark for showing the calculation
(4 × 1) + (2 × 2) + (4 × 3) + (1 × 4) + (5 × 5) + (0 × 6) + (8 × 7)
= 4 + 4 + 12 + 4 + 25 + 0 + 56 = 105
1 mark for any correct
line of working
105/11 = 9 remainder 6
check digit is: 6
[2]
(b) incorrect check digit
[1]
–
–
–
check digit should be 1
(3*1) + (2*2) + (4*3) + (0*4) + (0*5) + (4*6) + (5*7) // 3 + 4 + 12 + 0 + 0 + 24 + 35 //
Total = 78
78/11 gives 7 remainder 1
© Cambridge International Examinations 2016
[2]
Page 8
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
13
10
illegal access to a computer system
without the owner’s consent or
knowledge
Pharming
software that gathers information by
monitoring key presses on a user’s
keyboard; the information is relayed back
to the originator of the software
Phishing
Viruses
malicious code installed on the hard drive
of a user’s computer or on a web server;
this code will re-direct the user to a fake
website without the user’s knowledge
Hacking
creator of code sends out a legitimatelooking email in the hope of gathering
personal and financial information from
the recipient; it requires the user to click
on the link in the email or attachment
a message given to a web browser by a
web server; it is stored in a text file; the
message is then sent back to the server
each time the browser requests a page
from the server
Spyware
program or code that replicates itself
designed to amend, delete or copy data
or files on a user’s computer; often
causes the computer to crash or run
slowly
Cookies
5/6 matches – 5 marks
4 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
© Cambridge International Examinations 2016
[5]
Page 9
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
Paper
13
11 (a) 1 mark for each correct row
Single track
Many
concentric
tracks
Blue laser
Red laser
used to read/ used to read/
write data
write data
DVD-RW
DVD-RAM
CD-ROM
Blu-ray disc
1 mark
1 mark
1 mark
1 mark
[4]
(b) (i) Any three from:
–
–
–
–
–
–
–
–
don’t need to “get up to speed” to work properly/no latency
lower/less power consumption/more energy efficient
run cooler
run quieter
data access is faster
occupies less physical space/more compact
lighter, so more suitable for a portable computer/laptop
no moving parts so more reliable/durable in a portable computer/laptop
[3]
(ii) Any two from:
–
–
–
–
HDD is cheaper for larger amounts of storage space
HDD has greater longevity for read/write functions
Expensive to change the technology // HDD are trusted technology
No requirement for the increased speed of SSD
© Cambridge International Examinations 2016
[2]
Page 10
Mark Scheme
Cambridge IGCSE – May/June 2016
Syllabus
0478
12 (a) QR (quick response) Code
(b) –
Paper
13
[1]
A 5 0 (1 mark)
1
0
1
1 mark
0
0
1
0
1
0
0
1 mark
0
0
1 mark
[4]
(c) Any three from:
-
visitor scans the QR code with (the camera on) the mobile device
App is used to read/interpret the QR code
links to a website/opens a document …
… to access local tourist information
can store the QR code to refer to again for the information
© Cambridge International Examinations 2016
[3]
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 4 1 7 0 3 0 8 1 4 8 *
0478/11
COMPUTER SCIENCE
October/November 2016
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 14 printed pages and 2 blank pages.
DC (NH/JG) 118885/4
© UCLES 2016
[Turn over
2
1
To process an instruction, a central processing unit (CPU) goes through a cycle that has three
main stages.
Name each stage in this cycle.
Stage 1 ................................................................................
Stage 2 ................................................................................
Stage 3 ................................................................................
2
[3]
Name each of the potential security issues described in the five statements below:
Statement
Security issue
The act of gaining unauthorised access to
a computer system
..................................................................................
Program code that can replicate itself with
the intention of deleting or corrupting files
stored in a computer
..................................................................................
A small file sent by a web server to a web
browser; every time the user visits the
website, data about user preferences is
collected
..................................................................................
The act of illegally changing the source
code of a program so that it can be
exploited for another use
..................................................................................
Malicious code installed on a user’s hard
drive or a web server which redirects
the user to a fake website without their
knowledge
..................................................................................
[5]
© UCLES 2016
0478/11/O/N/16
3
3
Five computer terms and seven descriptions are shown below.
Draw a line to connect each computer term to its correct description.
Computer term
Serial, simplex data
transmission
Description
Several bits of data sent down several
wires, in both directions, but not at the
same time
Several bits of data sent down several
wires, in both directions, at the same
time
Parallel, half-duplex
data transmission
Parity check
An even or odd number of bits set to 1
in a byte, used to check if the byte has
been transmitted correctly
One bit sent at a time, over a single wire
in one direction only
An additional digit placed at the end of a
number to check if the number has been
entered correctly
Automatic repeat
request (ARQ)
A value transmitted at the end of a block
of data; it is calculated using the other
elements in the data stream and is used
to check for transmission errors
Checksum
© UCLES 2016
An error detection method that uses
response and time out when transmitting
data; if a response is not sent back to
the sender in an agreed amount of time,
then the data is re-sent
0478/11/O/N/16
[5]
[Turn over
4
4
The Henslows Diner is a local restaurant.
(a) Staff currently use a keyboard to input a customer food order into a computer. The food order
is then sent to the kitchen.
State two disadvantages of using a keyboard to input a customer food order.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
[2]
(b) A concept keyboard has a flat surface that is overlaid with images of food items available
from the restaurant menu. Staff can click on an image to add the food item to a customer food
order.
The Henslows Diner wants to change to a concept keyboard to input customer food orders.
Explain two benefits of making this change.
1 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2016
0478/11/O/N/16
5
(c) The Henslows Diner stores personal data on a computer. This computer is connected to the
Internet to allow the data to be backed up.
There is currently one security method in place to protect the data on the computer from
unauthorised access. This is a password.
Give two other security methods that could be added to improve the security of the data.
Describe how each method will keep the data safe.
Security method 1 .....................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Security method 2 .....................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2016
0478/11/O/N/16
[Turn over
6
5
Three switches, A, B and C, each send values of 0 or 1 to a logic circuit. Value X is output from the
logic circuit.
Switch A
Switch B
Logic circuit
Output X
Switch C
Output X has a value of 1 depending on the following conditions:
Switch A sends value 1 AND Switch B sends value 0
OR
Switch B sends value 1 AND Switch C sends value 0
(a) Draw a logic circuit to represent the conditions above.
A
B
X
C
[5]
© UCLES 2016
0478/11/O/N/16
7
(b) Complete the truth table for the conditions given at the start of question 5.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
(c) A microprocessor regularly samples the output, X. Each sample value is stored in an 8-bit
register as shown below. One bit of this register is reserved as a parity bit.
Five consecutive output values of 1 indicate a fault condition.
Identify which of the following registers shows a fault condition.
Parity bit
1
1
1
1
1
0
0
1
Register Y
0
1
0
1
1
1
1
1
Register Z
Register .............................................[1]
© UCLES 2016
0478/11/O/N/16
[Turn over
8
(d) When eight bytes of data have been collected, they are transmitted to a computer 100 km
away. Parity checks are carried out to identify if the data has been transmitted correctly. The
system uses even parity and column 1 is the parity bit.
The eight bytes of data are sent together with a ninth parity byte:
parity
bit
column
2
column
3
column
4
column
5
column
6
column
7
column
8
byte 1
1
0
0
0
0
1
0
0
byte 2
1
1
1
1
0
0
1
1
byte 3
0
1
0
0
1
0
0
0
byte 4
0
1
1
1
0
0
0
1
byte 5
1
0
0
0
1
1
1
1
byte 6
0
0
0
0
0
0
0
0
byte 7
1
1
1
0
1
0
0
0
byte 8
1
0
0
0
1
1
1
0
parity
byte
1
0
1
1
0
1
1
1
(i)
Identify which of the eight bytes contains an error.
byte ...............................................................................................................................[1]
(ii)
Identify which column contains an error.
column ...........................................................................................................................[1]
(iii)
The incorrect bit is indicated where the byte number and column cross.
Give the corrected byte.
[1]
(iv)
Calculate the denary value of the corrected byte.
...........................................................................................................................................
.......................................................................................................................................[1]
(v)
Considering the fault condition given in part (c), explain why it is very important that the
incorrect bit is located and corrected.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
© UCLES 2016
0478/11/O/N/16
9
6
High-level or low-level languages can be used when writing a computer program.
State two advantages of using a high-level language and two advantages of using a low-level
language.
High-level language advantage 1 ....................................................................................................
..........................................................................................................................................................
High-level language advantage 2 ....................................................................................................
..........................................................................................................................................................
Low-level language advantage 1 .....................................................................................................
..........................................................................................................................................................
Low-level language advantage 2 .....................................................................................................
..........................................................................................................................................................
[4]
7
Modern Liquid Crystal Display (LCD) monitors use Light-Emitting Diode (LED) backlit technology.
Give four benefits of using LED technology.
1 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
2 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
3 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
4 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
© UCLES 2016
0478/11/O/N/16
[Turn over
10
8
Four descriptions about compilers and interpreters are shown below.
Draw lines to indicate which descriptions refer to a compiler and which descriptions refer to an
interpreter.
Description
It is more difficult to debug the
code since one error can
produce many other associated
errors.
The speed of execution of
program loops is slower.
Compiler
It produces fast, executable
code that runs directly on the
processor.
Interpreter
It is easier to debug the code
since an error is displayed as
soon as it is found.
[4]
© UCLES 2016
0478/11/O/N/16
11
9
A security light is controlled by sensors and a microprocessor.
Describe how the sensors and microprocessor interact to switch on the security light when an
intruder is detected.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[6]
© UCLES 2016
0478/11/O/N/16
[Turn over
12
10 (a) A manufacturer of aeroplane engines assigns a denary identification number (ID) to each
engine.
One engine has the ID:
(i)
0431
Convert this denary number to a 12-bit binary format.
[2]
(ii)
Show how this number would be represented in hexadecimal.
...........................................................................................................................................
...........................................................................................................................................
[3]
(b) The current status of the engine is sent to a computer in the aeroplane.
Each piece of data collected is 8 bytes in size. Data collection occurs every 30 seconds.
Calculate the number of kilobytes that would be needed to store the data collected during a
10-hour flight. Show your working.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
................................................. kilobytes
[3]
© UCLES 2016
0478/11/O/N/16
13
(c) At the end of the flight, all of the data are sent to the aeroplane engine manufacturer using the
Internet.
The computer in the aeroplane has a MAC address and an IP address.
State what is meant by these two terms.
MAC address ............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
IP address .................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(d) When sending this data, security is very important. Data are sent over the Internet using
Transport Layer Security (TLS) protocol.
Name the two layers that make up TLS.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
© UCLES 2016
0478/11/O/N/16
[Turn over
14
11
Explain why ethics are important when using computers.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[6]
© UCLES 2016
0478/11/O/N/16
15
BLANK PAGE
© UCLES 2016
0478/11/O/N/16
16
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2016
0478/11/O/N/16
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
Paper 1
October/November 2016
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the October/November 2016 series for most
Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level
components.
® IGCSE is the registered trademark of Cambridge International Examinations.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 9 printed pages.
© UCLES 2016
[Turn over
Page 2
1
2
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
11
In any order:
– Fetch
– Decode
– Execute
[3]
–
–
–
–
–
[5]
Hacking
Virus
Cookies
Cracking
Pharming
© UCLES 2016
Page 3
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
11
3
[5]
© UCLES 2016
Page 4
4
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
11
(a) Any two from:
–
–
–
Easy to make a mistake
Can be slow if not trained
Dirt/food can get into keys
[2]
(b) Any two with identification and explanation from:
–
–
–
–
–
–
–
–
Fewer typing errors may be made …
… because one button is pressed to order an item
Speed up the time to enter an order …
… because fewer buttons are pressed to complete the order
May require less training …
… because it is easier to identify an order item from its image rather than typing it
Can stop dirt/food damage …
… normally has a protective layer // because there are no keys for dirt/food to get into
[4]
(c) 1 mark for security measure, 1 mark for description.
Any two from:
–
–
Encryption
If the data is accessed or stolen it will be meaningless
–
–
Biometric device
Can help prevents unauthorised access to the system (only award once)
–
–
–
–
Firewall
Can alert to show unauthorised access attempt on the system
Can help prevent unauthorised access to the system (only award once)
Can help protect against viruses and malware entering the system
–
–
Anti-spyware
Can stop the keys being logged that, when analysed, would reveal the password to
the data
© UCLES 2016
[4]
Page 5
5
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
11
(a) 1 mark per correct section.
A
X
B
C
[5]
(b) 4 marks for 8 correct values
3 marks for 6 correct values
2 marks for 4 correct values
1 mark for 2 correct values
Working space
A
B
C
X
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
[4]
© UCLES 2016
Page 6
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
11
(c) Register Z
[1]
(d) (i) (byte) 5
[1]
(ii) (column) 4
[1]
(iii) corrected byte is: 1 0 0 1 1 1 1 1
[1]
(iv) that gives the value: 1 5 9
(follow through applies)
[1]
(v) Any two from:
–
–
6
The byte would be transmitted without having 5 consecutive 1’s
The fault condition would not be recognised
[2]
Any two from:
High level language
–
–
–
–
easier/faster to write code as uses English-like statements
easier to modify as uses English-like statements
easier to debug as uses English-like statements
portable language code
Any two from:
Low level language
–
–
–
7
can work directly on memory locations
can be executed faster
translated program requires less memory
[4]
Any four from:
–
–
–
–
–
–
reaches maximum brightness quickly
colours are vivid
good colour definition/contrast can be achieved
screens can be thinner/thin
more reliable as LED’s are long lasting
consume very little/less energy
© UCLES 2016
[4]
Page 7
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
11
8
It is more difficult to debug the
code since one error can
produce many other
associated errors
The speed of execution of
program loops is slower.
Compiler
It produces fast, executable
code that runs directly on the
processor
Interpreter
It is easier to debug the code
since an error is displayed as
soon as it is found.
[4]
© UCLES 2016
Page 8
9
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
11
Any six from:
–
–
–
–
–
–
–
–
–
–
–
–
infrared / motion / pressure (sensor) // sensor detects movement/pressure
signals/data sent (continuously) to microprocessor
converted from analogue to digital (using ADC)
microprocessor compares value with those stored in memory
if sensor value does not match the stored value(s) …
… signal sent to switch on the light
… signal sent to keep the light on
… light remains on for a period of time (30 seconds)
if sensor value matches the stored value(s) …
… light will remain off
… will turn off after period of time (30 seconds)
works in a continues loop
[6]
10 (a) (i) 2 marks for 3 correct binary conversions, 1 mark for 2 correct binary conversions
0
0
0
1
1
0
1
0
1
1
1
[2]
1
(ii) 1 mark for each correct hex value converted
1AF
[3]
(b) 2 marks for working + 1 mark for correct answer
Working
– 1200 × 8 = 9600 (bytes)
– 9600/1024 or 9600/1000
Answer
– 9.4 or 9.6 kilobytes
[3]
(c) Any one from:
MAC address
–
–
–
–
Media Access Control (address)
unique number that identifies a device (connected to the Internet)
address is made up of manufacturer id + serial number of device
address is allocated by the manufacturer
Any one from:
IP address
–
–
–
–
–
Internet Protocol (address)
location/address of a device on the Internet
address is unique for given Internet session
address is supplied when a device connects to the Internet
address is allocated by the network
© UCLES 2016
[2]
Page 9
(d) –
–
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
record (layer)
handshake (layer)
Paper
11
[2]
11 Any six from:
– Help stop the misuse of computers
– The use of computers needs to be governed
– Help keep users safer when using computers
– Provides rules for using computers
– Help stop intellectual property theft
– Helps prevent the misuse of personal information
– Reference to laws (relevant example)
– Reference to security issues (relevant example)
NOTE: Answer must refer to the importance of ethics and be more than a description of
ethics.
© UCLES 2016
[6]
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 0 7 2 0 8 2 9 7 4 7 *
0478/12
COMPUTER SCIENCE
October/November 2016
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
DC (NH/SW) 122184/3
© UCLES 2016
[Turn over
2
1
(a) Give two reasons why a programmer would choose to write code in a low-level language.
1 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(b) High-level languages require either an interpreter or a compiler to translate the program.
The table below lists a number of statements about language translators.
Tick (3) to show which statements refer to interpreters and which refer to compilers.
Statements
Interpreter (3)
Compiler (3)
Translates the source code into machine code
all at once
Produces an executable file in machine code
Executes a high-level language program one
instruction at a time
Once translated, the translator does not need to
be present for the program to run
An executable file is produced
[5]
2
State four functions of an operating system.
1 .......................................................................................................................................................
2 .......................................................................................................................................................
3 .......................................................................................................................................................
4 .......................................................................................................................................................
[4]
© UCLES 2016
0478/12/O/N/16
3
3
(a) Explain what is meant by:
(i)
Serial data transmission
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(ii)
Parallel data transmission
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(b) A computer in a factory is connected to a printer. The printer is located in an office 1 km away
from the factory.
Identify which data transmission method would be most suitable for this connection.
...................................................................................................................................................
Give two reasons for your choice.
1 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2016
0478/12/O/N/16
[Turn over
4
4
Nine bytes of data are transmitted from one computer to another. Even parity is used. An additional
parity byte is also sent.
The ten bytes arrive at the destination computer as follows:
parity bit
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
bit 8
byte 1
1
1
1
0
1
1
1
0
byte 2
0
0
0
0
0
1
0
1
byte 3
0
1
1
1
1
0
0
0
byte 4
1
1
0
0
0
0
0
0
byte 5
1
0
1
1
1
1
1
0
byte 6
0
1
0
1
1
0
0
1
byte 7
0
1
1
1
0
0
1
1
byte 8
0
0
1
1
0
1
1
0
byte 9
1
1
0
0
0
0
1
1
parity byte
0
0
1
0
0
0
1
0
One of the bits was corrupted during the data transmission.
(a) Circle the corrupt bit in the corrupt byte in the table above.
[1]
(b) Explain how the corrupted bit was found.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
© UCLES 2016
0478/12/O/N/16
5
5
A computer uses an 8-bit register.
The 8-bit register contains binary integers.
(a) Write the denary (base 10) value represented by:
128
64
32
16
8
4
2
1
0
1
1
1
0
0
0
0
...............................................................................................................................................[1]
(b) All the bits in the register are shifted one place to the right as shown below.
0
1
1
1
0
0
0
0
0
0
1
1
1
0
0
0
Write the denary number that is represented after this shift.
...............................................................................................................................................[1]
(c) State the effect the shift to the right had on the original denary number from part (a).
...............................................................................................................................................[1]
(d) The original number in part (a) is shifted three places to the right.
(i)
Show the new binary number:
[1]
(ii)
Write the equivalent denary number.
.......................................................................................................................................[1]
© UCLES 2016
0478/12/O/N/16
[Turn over
6
(e) Describe the problems that could be caused if the original binary number in part (a) is shifted
five places to the right.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
6
Four computer terms and eight descriptions are shown below.
Draw lines to connect each computer term to the correct description(s).
Computer term
Description
Data can be read but not altered
Arithmetic and logic
unit (ALU)
Carries out operations such as
addition and multiplication
Stores bootstrap loader and BIOS
Control unit
Fetches each instruction in turn
Carries out operations such as
AND, OR, NOT
Random access
memory (RAM)
Stores part of the operating system
currently in use
Read only memory
(ROM)
Stores data currently in use
Manages execution of each
instruction
[4]
© UCLES 2016
0478/12/O/N/16
7
7
(a) Complete the truth tables and name the single logic gate that could replace each logic circuit:
(i)
A
B
X
A
B
0
0
0
1
1
0
1
1
Working space
X
Single logic gate ............................................................................................................[3]
(ii)
A
X
B
A
B
0
0
0
1
1
0
1
1
Working space
X
Single logic gate ............................................................................................................[3]
© UCLES 2016
0478/12/O/N/16
[Turn over
8
(b) (i)
Draw a logic circuit to represent the following logic statement:
X = 1 if (A = 1 AND B = 1) OR ( (B = NOT 1) AND C = 1)
A
B
X
C
[4]
(ii)
Complete the truth table for the logic statement in part (b)(i).
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2016
0478/12/O/N/16
9
8
Identify whether the four statements about file compression are correct by writing TRUE or FALSE
in the following table.
Statement
TRUE or FALSE
MIDI files store the actual music notes in a compressed format
JPEG files are examples of lossless file compression
MP3 files are, on average, 90% smaller than the music files
stored on a CD
MP4 files are examples of lossy file compression
[4]
9
(a) Explain what is meant by a denial of service attack.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(b) Name and describe two other potential security threats when using the Internet.
Security threat 1 .......................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Security threat 2 .......................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2016
0478/12/O/N/16
[Turn over
10
10 (a) Describe what is meant by HTML.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
(b) The following URL is typed in:
http://www.cie.org.uk/ComputerSciencePapers
This URL is composed of three parts.
State the part of this URL that is the:
File name ..................................................................................................................................
Protocol ....................................................................................................................................
Web server name .....................................................................................................................
[3]
© UCLES 2016
0478/12/O/N/16
11
11
A security system is installed in a house. A hexadecimal number is entered to activate or deactivate
the alarm.
(a) The alarm code is set to hexadecimal number 2 A F
Show how this number would be stored in a 12-bit binary register.
[3]
(b) Identify two sensors that the security system could use to detect intruders.
Describe how each sensor could be used in the security system.
Sensor 1 ...................................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Sensor 2 ...................................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2016
0478/12/O/N/16
[Turn over
12
12 Explain the differences between freeware and free software.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[4]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2016
0478/12/O/N/16
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
Paper 1
October/November 2016
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the October/November 2016 series for most
Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level
components.
® IGCSE is the registered trademark of Cambridge International Examinations.
This document consists of 10 printed pages.
© UCLES 2016
[Turn over
Page 2
1
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
(a) Any two from:
–
–
–
direct access to computer processor / special hardware // machine dependent
instructions
uses up less memory
can increase the speed of processing a program // executes instructions faster
[2]
(b)
Interpreter (9)
Statements
Compiler (9)
Translates the source code into machine code
all at once
9
Produces an executable file in machine code
9
Executes a high-level language program one
instruction at a time
9
Once translated, the translator does not need to be
present for the program to run
9
An executable file is produced
9
[5]
2
Any four from:
–
–
–
–
–
–
–
–
–
–
–
–
Provides a user interface
Handles interrupts / errors
Memory management
File management
Manages peripherals (inputs/outputs)
Provides security methods
Allows multitasking
Manages multiprogramming
Enables batch processing
Manages software installation / removal
Allows creation of multiple accounts
Levels of access
[4]
© UCLES 2016
Page 3
3
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
(a) (i) Any two from:
serial
–
–
–
one bit sent at a time // bits sent sequentially
over a single wire
synchronous or asynchronous
[2]
(ii) Any two from:
parallel
–
–
–
several bits / a byte sent at a time
using many / multiple wires
synchronous
[2]
(b)
–
serial
Any two from:
–
–
–
–
–
serial data transmission more reliable over long distances
less likely for the data to be skewed/out of synchronisation
less interference as only a single wire
it is a cheaper connection as only single wire needed // cheaper to set up
a fast connection is not required as a printer is limited by its printing speed
[3]
4
(a) Intersection of Row 7 and column 4 circled
(b) –
–
[1]
Row (byte number) 7 has an odd number of 1s (five 1s)
Column (bit number) 4 has an odd number of 1s (five 1s)
[2]
© UCLES 2016
Page 4
5
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
(a) 112
[1]
(b) 56
[1]
(c) divided by 2 // value 112 was halved // multiplied by 0.5
[1]
(d) (i)
0
0
0
0
1
1
1
0
[1]
(ii) 14
[1]
(e) Any two from:
–
–
–
–
run out of places to the right of register / at the end of register
right-most 1 would be lost
number would become 3 instead of 3.5
loss of precision
[2]
© UCLES 2016
Page 5
6
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
1 mark for both correct lines from each computer term.
[4]
© UCLES 2016
Page 6
7
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
(a) (i) 2 marks for 4 correct outputs,
1 mark for 2 correct outputs
1 mark for correct gate
A
B
Working space
X
0
0
0
0
1
0
1
0
0
1
1
1
AND gate
[3]
(ii) 2 marks for 4 correct outputs
1 mark for 2 correct outputs
1 mark for correct gate
A
B
Working space
X
0
0
0
0
1
1
1
0
1
1
1
1
OR gate
[3]
© UCLES 2016
Page 7
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
(b)(i) 1 mark per correct section.
1 mark
1 mark
1 mark
1 mark
[4]
(ii) 4 marks for 8 correct outputs
3 marks for 6 correct outputs
2 marks for 4 correct outputs
1 mark for 2 correct outputs
A
B
C
Working space
X
0
0
0
0
0
0
1
1
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
1
[4]
© UCLES 2016
Page 8
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
8
Statement
TRUE or FALSE
MIDI stores the actual music notes in a compressed format
FALSE
JPEG files are examples of lossless file compression
FALSE
MP3 files are, on average, 90% smaller than the music files
stored on a CD
TRUE
MP4 files are examples of lossy file compression
TRUE
[4]
9
(a) Any two from:
–
–
–
–
a large number of requests are sent to the network/server all at once
designed to flood a network/server with useless traffic/requests
the network/server will come to a halt/stop trying to deal with all the traffic/requests
prevents users from gaining access to a website/server
[2]
(b) 1 mark for each security threat and 1 mark for matching description
Security threat
Description
Viruses
– software that replicates
– causes loss/corruption of data // computer may “crash”/run
slow
Hacking/cracking
– illegal/ unauthorised access to a system/data
Phishing
– a link/attachment sends user to fake website (where personal
data may be obtained)
Pharming
– malicious code installed on user’s hard drive / computer
– user is redirected to a fake website (where personal data may
be obtained)
Spyware/key logger
– send/relay key strokes to a third party
[4]
© UCLES 2016
Page 9
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
10 (a) Any three from:
–
–
–
–
hyper text mark-up language
uses both structure and presentation
web-authoring language/software // used to create websites/webpages
uses tags to define e.g. colour / font / graphics / layout
[3]
(b)
File name:
ComputerSciencePapers
Protocol:
http(://)
Web server name:
www.cie.org.uk
[3]
11 (a) 1 mark per nibble
0010
1010
1111
[3]
(b) 1 mark for identification of each sensor, max 2 for each description
Infrared/motion sensor
–
–
–
–
–
Receives infrared rays/heat
Sends data to microprocessor
Receives microwaves
Placed in the corner of a room, across a doorway
Used to detect the heat of an intruder // used to detect if an infrared beam has been
broken by an intruder
Pressure sensor
–
–
–
–
Receives current if circuit created // stops receiving current if circuit is broken
Sends data to microprocessor
Placed on a window/door, at the entrance
Used to detect a change in pressure
[6]
© UCLES 2016
Page 10
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
12
12 Any four from:
–
–
–
–
–
Freeware needs owner’s permission to share/copy/amend whereas free software can be
shared/copied/amended without permission
Freeware the owner retains copyright / is subject to copyright whereas free software the
owner releases copyright/ is not subject to copyright
Freeware is normally provided without a fee whereas free software a fee may be charged
Freeware is distributed without the source code whereas free software is distributed with the
source code
Freeware can be restricted in use e.g. non-commercial whereas free software can be used
without restriction
NOTE: The question asks candidates to explain the differences, so each mark needs to have a
comparison.
[4]
© UCLES 2016
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 0 0 5 8 7 0 8 2 2 7 *
0478/13
COMPUTER SCIENCE
October/November 2016
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 14 printed pages and 2 blank pages.
DC (SLM) 135990
© UCLES 2016
[Turn over
2
1
To process an instruction, a central processing unit (CPU) goes through a cycle that has three
main stages.
Name each stage in this cycle.
Stage 1 ................................................................................
Stage 2 ................................................................................
Stage 3 ................................................................................
2
[3]
Name each of the potential security issues described in the five statements below:
Statement
Security issue
The act of gaining unauthorised access to
a computer system
..................................................................................
Program code that can replicate itself with
the intention of deleting or corrupting files
stored in a computer
..................................................................................
A small file sent by a web server to a web
browser; every time the user visits the
website, data about user preferences is
collected
..................................................................................
The act of illegally changing the source
code of a program so that it can be
exploited for another use
..................................................................................
Malicious code installed on a user’s hard
drive or a web server which redirects
the user to a fake website without their
knowledge
..................................................................................
[5]
© UCLES 2016
0478/13/O/N/16
3
3
Five computer terms and seven descriptions are shown below.
Draw a line to connect each computer term to its correct description.
Computer term
Serial, simplex data
transmission
Description
Several bits of data sent down several
wires, in both directions, but not at the
same time
Several bits of data sent down several
wires, in both directions, at the same
time
Parallel, half-duplex
data transmission
Parity check
An even or odd number of bits set to 1
in a byte, used to check if the byte has
been transmitted correctly
One bit sent at a time, over a single wire
in one direction only
An additional digit placed at the end of a
number to check if the number has been
entered correctly
Automatic repeat
request (ARQ)
A value transmitted at the end of a block
of data; it is calculated using the other
elements in the data stream and is used
to check for transmission errors
Checksum
© UCLES 2016
An error detection method that uses
response and time out when transmitting
data; if a response is not sent back to
the sender in an agreed amount of time,
then the data is re-sent
0478/13/O/N/16
[5]
[Turn over
4
4
The Henslows Diner is a local restaurant.
(a) Staff currently use a keyboard to input a customer food order into a computer. The food order
is then sent to the kitchen.
State two disadvantages of using a keyboard to input a customer food order.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
[2]
(b) A concept keyboard has a flat surface that is overlaid with images of food items available
from the restaurant menu. Staff can click on an image to add the food item to a customer food
order.
The Henslows Diner wants to change to a concept keyboard to input customer food orders.
Explain two benefits of making this change.
1 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2016
0478/13/O/N/16
5
(c) The Henslows Diner stores personal data on a computer. This computer is connected to the
Internet to allow the data to be backed up.
There is currently one security method in place to protect the data on the computer from
unauthorised access. This is a password.
Give two other security methods that could be added to improve the security of the data.
Describe how each method will keep the data safe.
Security method 1 .....................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Security method 2 .....................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2016
0478/13/O/N/16
[Turn over
6
5
Three switches, A, B and C, each send values of 0 or 1 to a logic circuit. Value X is output from the
logic circuit.
Switch A
Switch B
Logic circuit
Output X
Switch C
Output X has a value of 1 depending on the following conditions:
Switch A sends value 1 AND Switch B sends value 0
OR
Switch B sends value 1 AND Switch C sends value 0
(a) Draw a logic circuit to represent the conditions above.
A
B
X
C
[5]
© UCLES 2016
0478/13/O/N/16
7
(b) Complete the truth table for the conditions given at the start of question 5.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
(c) A microprocessor regularly samples the output, X. Each sample value is stored in an 8-bit
register as shown below. One bit of this register is reserved as a parity bit.
Five consecutive output values of 1 indicate a fault condition.
Identify which of the following registers shows a fault condition.
Parity bit
1
1
1
1
1
0
0
1
Register Y
0
1
0
1
1
1
1
1
Register Z
Register .............................................[1]
© UCLES 2016
0478/13/O/N/16
[Turn over
8
(d) When eight bytes of data have been collected, they are transmitted to a computer 100 km
away. Parity checks are carried out to identify if the data has been transmitted correctly. The
system uses even parity and column 1 is the parity bit.
The eight bytes of data are sent together with a ninth parity byte:
parity
bit
column
2
column
3
column
4
column
5
column
6
column
7
column
8
byte 1
1
0
0
0
0
1
0
0
byte 2
1
1
1
1
0
0
1
1
byte 3
0
1
0
0
1
0
0
0
byte 4
0
1
1
1
0
0
0
1
byte 5
1
0
0
0
1
1
1
1
byte 6
0
0
0
0
0
0
0
0
byte 7
1
1
1
0
1
0
0
0
byte 8
1
0
0
0
1
1
1
0
parity
byte
1
0
1
1
0
1
1
1
(i)
Identify which of the eight bytes contains an error.
byte ...............................................................................................................................[1]
(ii)
Identify which column contains an error.
column ...........................................................................................................................[1]
(iii)
The incorrect bit is indicated where the byte number and column cross.
Give the corrected byte.
[1]
(iv)
Calculate the denary value of the corrected byte.
...........................................................................................................................................
.......................................................................................................................................[1]
(v)
Considering the fault condition given in part (c), explain why it is very important that the
incorrect bit is located and corrected.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
© UCLES 2016
0478/13/O/N/16
9
6
High-level or low-level languages can be used when writing a computer program.
State two advantages of using a high-level language and two advantages of using a low-level
language.
High-level language advantage 1 ....................................................................................................
..........................................................................................................................................................
High-level language advantage 2 ....................................................................................................
..........................................................................................................................................................
Low-level language advantage 1 .....................................................................................................
..........................................................................................................................................................
Low-level language advantage 2 .....................................................................................................
..........................................................................................................................................................
[4]
7
Modern Liquid Crystal Display (LCD) monitors use Light-Emitting Diode (LED) backlit technology.
Give four benefits of using LED technology.
1 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
2 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
3 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
4 .......................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
© UCLES 2016
0478/13/O/N/16
[Turn over
10
8
Four descriptions about compilers and interpreters are shown below.
Draw lines to indicate which descriptions refer to a compiler and which descriptions refer to an
interpreter.
Description
It is more difficult to debug the
code since one error can
produce many other associated
errors.
The speed of execution of
program loops is slower.
Compiler
It produces fast, executable
code that runs directly on the
processor.
Interpreter
It is easier to debug the code
since an error is displayed as
soon as it is found.
[4]
© UCLES 2016
0478/13/O/N/16
11
9
A security light is controlled by sensors and a microprocessor.
Describe how the sensors and microprocessor interact to switch on the security light when an
intruder is detected.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[6]
© UCLES 2016
0478/13/O/N/16
[Turn over
12
10 (a) A manufacturer of aeroplane engines assigns a denary identification number (ID) to each
engine.
One engine has the ID:
(i)
0431
Convert this denary number to a 12-bit binary format.
[2]
(ii)
Show how this number would be represented in hexadecimal.
...........................................................................................................................................
...........................................................................................................................................
[3]
(b) The current status of the engine is sent to a computer in the aeroplane.
Each piece of data collected is 8 bytes in size. Data collection occurs every 30 seconds.
Calculate the number of kilobytes that would be needed to store the data collected during a
10-hour flight. Show your working.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
................................................. kilobytes
[3]
© UCLES 2016
0478/13/O/N/16
13
(c) At the end of the flight, all of the data are sent to the aeroplane engine manufacturer using the
Internet.
The computer in the aeroplane has a MAC address and an IP address.
State what is meant by these two terms.
MAC address ............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
IP address .................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(d) When sending this data, security is very important. Data are sent over the Internet using
Transport Layer Security (TLS) protocol.
Name the two layers that make up TLS.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
© UCLES 2016
0478/13/O/N/16
[Turn over
14
11
Explain why ethics are important when using computers.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[6]
© UCLES 2016
0478/13/O/N/16
15
BLANK PAGE
© UCLES 2016
0478/13/O/N/16
16
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2016
0478/13/O/N/16
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
Paper 1
October/November 2016
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the October/November 2016 series for most
Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level
components.
® IGCSE is the registered trademark of Cambridge International Examinations.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 9 printed pages.
© UCLES 2016
[Turn over
Page 2
1
2
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
13
In any order:
– Fetch
– Decode
– Execute
[3]
–
–
–
–
–
[5]
Hacking
Virus
Cookies
Cracking
Pharming
© UCLES 2016
Page 3
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
13
3
[5]
© UCLES 2016
Page 4
4
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
13
(a) Any two from:
–
–
–
Easy to make a mistake
Can be slow if not trained
Dirt/food can get into keys
[2]
(b) Any two with identification and explanation from:
–
–
–
–
–
–
–
–
Fewer typing errors may be made …
… because one button is pressed to order an item
Speed up the time to enter an order …
… because fewer buttons are pressed to complete the order
May require less training …
… because it is easier to identify an order item from its image rather than typing it
Can stop dirt/food damage …
… normally has a protective layer // because there are no keys for dirt/food to get into
[4]
(c) 1 mark for security measure, 1 mark for description.
Any two from:
–
–
Encryption
If the data is accessed or stolen it will be meaningless
–
–
Biometric device
Can help prevents unauthorised access to the system (only award once)
–
–
–
–
Firewall
Can alert to show unauthorised access attempt on the system
Can help prevent unauthorised access to the system (only award once)
Can help protect against viruses and malware entering the system
–
–
Anti-spyware
Can stop the keys being logged that, when analysed, would reveal the password to
the data
© UCLES 2016
[4]
Page 5
5
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
13
(a) 1 mark per correct section.
A
X
B
C
[5]
(b) 4 marks for 8 correct values
3 marks for 6 correct values
2 marks for 4 correct values
1 mark for 2 correct values
Working space
A
B
C
X
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
[4]
© UCLES 2016
Page 6
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
13
(c) Register Z
[1]
(d) (i) (byte) 5
[1]
(ii) (column) 4
[1]
(iii) corrected byte is: 1 0 0 1 1 1 1 1
[1]
(iv) that gives the value: 1 5 9
(follow through applies)
[1]
(v) Any two from:
–
–
6
The byte would be transmitted without having 5 consecutive 1’s
The fault condition would not be recognised
[2]
Any two from:
High level language
–
–
–
–
easier/faster to write code as uses English-like statements
easier to modify as uses English-like statements
easier to debug as uses English-like statements
portable language code
Any two from:
Low level language
–
–
–
7
can work directly on memory locations
can be executed faster
translated program requires less memory
[4]
Any four from:
–
–
–
–
–
–
reaches maximum brightness quickly
colours are vivid
good colour definition/contrast can be achieved
screens can be thinner/thin
more reliable as LED’s are long lasting
consume very little/less energy
© UCLES 2016
[4]
Page 7
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
13
8
It is more difficult to debug the
code since one error can
produce many other
associated errors
The speed of execution of
program loops is slower.
Compiler
It produces fast, executable
code that runs directly on the
processor
Interpreter
It is easier to debug the code
since an error is displayed as
soon as it is found.
[4]
© UCLES 2016
Page 8
9
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
Paper
13
Any six from:
–
–
–
–
–
–
–
–
–
–
–
–
infrared / motion / pressure (sensor) // sensor detects movement/pressure
signals/data sent (continuously) to microprocessor
converted from analogue to digital (using ADC)
microprocessor compares value with those stored in memory
if sensor value does not match the stored value(s) …
… signal sent to switch on the light
… signal sent to keep the light on
… light remains on for a period of time (30 seconds)
if sensor value matches the stored value(s) …
… light will remain off
… will turn off after period of time (30 seconds)
works in a continues loop
[6]
10 (a) (i) 2 marks for 3 correct binary conversions, 1 mark for 2 correct binary conversions
0
0
0
1
1
0
1
0
1
1
1
[2]
1
(ii) 1 mark for each correct hex value converted
1AF
[3]
(b) 2 marks for working + 1 mark for correct answer
Working
– 1200 × 8 = 9600 (bytes)
– 9600/1024 or 9600/1000
Answer
– 9.4 or 9.6 kilobytes
[3]
(c) Any one from:
MAC address
–
–
–
–
Media Access Control (address)
unique number that identifies a device (connected to the Internet)
address is made up of manufacturer id + serial number of device
address is allocated by the manufacturer
Any one from:
IP address
–
–
–
–
–
Internet Protocol (address)
location/address of a device on the Internet
address is unique for given Internet session
address is supplied when a device connects to the Internet
address is allocated by the network
© UCLES 2016
[2]
Page 9
(d) –
–
Mark Scheme
Cambridge IGCSE – October/November 2016
Syllabus
0478
record (layer)
handshake (layer)
Paper
13
[2]
11 Any six from:
– Help stop the misuse of computers
– The use of computers needs to be governed
– Help keep users safer when using computers
– Provides rules for using computers
– Help stop intellectual property theft
– Helps prevent the misuse of personal information
– Reference to laws (relevant example)
– Reference to security issues (relevant example)
NOTE: Answer must refer to the importance of ethics and be more than a description of
ethics.
© UCLES 2016
[6]
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 3 7 7 1 2 0 0 4 7 9 *
0478/11
COMPUTER SCIENCE
May/June 2017
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
DC (LK/SG) 125857/3
© UCLES 2017
[Turn over
2
1
The memory of a computer contains data and instructions in binary.
The following instruction is stored in a location of the memory.
0
0
1
0
1
0
0
1
1
1
1
1
1
1
0
0
(a) Convert the instruction into hexadecimal.
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................... [2]
(b) Explain why a programmer might prefer to read the instruction in hexadecimal rather than in
binary.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................... [2]
(c) Give two other uses of hexadecimal.
Use 1 ........................................................................................................................................
...................................................................................................................................................
Use 2 ........................................................................................................................................
...................................................................................................................................................
[2]
2
Programmers can use a high-level language to write a computer program.
(a) Explain what is meant by the term ‘high-level language’.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2017
0478/11/M/J/17
3
(b) A program written in a high-level language is translated into machine code. This is so that it
can be processed by a computer.
Name one type of translator that can be used.
.............................................................................................................................................. [1]
(c) Describe how your answer to part (b) translates this program.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [3]
3
Steffi has a number of files of different sizes that contain her work.
Tick (3) to show whether each statement is true or false.
true
(3)
Statement
false
(3)
47KB is larger than 10MB.
250bytes is smaller than 0.5MB.
50GB is larger than 100MB.
1TB is smaller than 4GB.
[4]
© UCLES 2017
0478/11/M/J/17
[Turn over
4
4
Five statements about serial half-duplex data transmission are shown in the table below.
Tick (3) to show whether each statement is true or false.
Statement
true
(3)
false
(3)
Data is transmitted in one direction only, one bit at a time.
Data is transmitted in both directions, multiple bits at a time.
Data is transmitted in one direction only, multiple bits at a time.
Data is transmitted in both directions, but only one direction at a
time. Data is transmitted one bit at a time.
Data is transmitted in both directions, but only one direction at a
time. Data is transmitted multiple bits at a time.
© UCLES 2017
0478/11/M/J/17
[5]
5
5
(a) Parity checks are often used to detect errors that may occur during data transmission.
The received bytes in the table below were transmitted using odd parity.
Tick (3) to show whether each byte has been corrupted during transmission or not
corrupted during transmission.
Received byte
corrupted
during
transmission
(3)
not corrupted
during
transmission
(3)
10110100
01101101
10000001
[3]
(b) Another method of error detection is Automatic Repeat reQuest (ARQ).
Explain how ARQ is used in error detection.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2017
0478/11/M/J/17
[Turn over
6
6
Signals are sent to and from the components of a processor using buses.
Identify and describe the purpose of two different buses.
Bus 1 ....................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Bus 2 ....................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2017
0478/11/M/J/17
7
7
Six security terms and six statements are listed below.
Draw a line to match the security term with the most appropriate statement.
Security term
Statement
Encryption
Provides a secure connection between
web browsers and websites allowing
secure transmission of private data.
Secure Socket
Layer (SSL)
Computer that acts as an intermediary
between a web browser and the
Internet.
Pharming
Legitimate-looking email is sent in the
hope of gathering personal information;
it requires the user to click on a link in
the email.
Phishing
Uses rules and criteria, set by the user,
to help protect a network or system from
unauthorised access.
Firewall
Malicious code installed on the hard
drive of a user’s computer; this code
will redirect the user to a fake website
without the user’s knowledge.
Proxy server
Scrambles data for secure transmission.
[5]
© UCLES 2017
0478/11/M/J/17
[Turn over
8
8
Complete the paragraph by choosing six correct terms from the list.
•
•
•
•
•
•
•
•
•
Optical
On-line
RAM
HDD
Primary
SSD
Secondary
ROM
Off-line
A computer has two different types of memory. .................................... memory is not directly
accessed by the CPU, but it allows a user to store data that can easily be accessed by applications.
Two examples of this type of memory are .................................... and .................................... . The
second type of memory is .................................... memory. This memory is directly accessed by
the CPU. It allows the processor to access data and instructions that are stored in this memory.
Two examples of this memory are .................................... and .................................... .
© UCLES 2017
0478/11/M/J/17
[6]
9
9
A supermarket has a system that allows customers to check out their own shopping.
Identify and describe the purpose of two input devices and one output device used in this system.
Input device 1 ...................................................................................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Input device 2 ...................................................................................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Output device 1 ................................................................................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
10 (a) Complete the truth table for the NOR gate.
A
X
B
A
B
0
0
0
1
1
0
1
1
Output (X)
[1]
© UCLES 2017
0478/11/M/J/17
[Turn over
10
(b) Write a logic statement that corresponds with the following logic circuit.
A
B
X
C
X = ..................................................................................................................................... [3]
11
State three functions provided by an operating system.
Function 1 ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Function 2 ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Function 3 ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[3]
© UCLES 2017
0478/11/M/J/17
11
12 The processes in a chemical factory are monitored by sensors connected to a microprocessor.
(a) Identify two different sensors used in this application. Give an example of how each sensor
could be used in the chemical factory.
Sensor 1 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
Sensor 2 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
[4]
(b) Describe how the sensors and a microprocessor are used to monitor a process.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [5]
© UCLES 2017
0478/11/M/J/17
[Turn over
12
13 (a) Gurdeep wants to send a large file to Jennifer over the Internet.
State two benefits of compressing the file to send it.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(b) Two types of compression are lossy and lossless.
Choose the most suitable type of compression for the following and explain your choice.
(i)
Downloading the code for a computer program:
Type of compression .........................................................................................................
Explanation .......................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
(ii)
Streaming a video file:
Type of compression .........................................................................................................
Explanation .......................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017
0478/11/M/J/17
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
Paper 1
May/June 2017
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2017 series for most Cambridge IGCSE®,
Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level
components.
® IGCSE is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 8 printed pages.
© UCLES 2017
[Turn over
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
May/June 2017
Answer
Marks
1(a)
1 mark for any two correct values, 2 marks for all 4 correct values.
29FC
2
1(b)
Two from:
• Easier/quicker to understand/read
• Easier to debug/identify errors
• Fewer digits are used / shorter // takes up less space on screen // more
can be shown on screen / page
2
1(c)
Two from:
• Notations for colour in HTML // HTML colour (codes)
• Error messages
• MAC address // IP address
• Locations in memory
• Memory dump
2
Question
Answer
2(a)
Two from:
• Closer to human language // closer to English
• Independent of a particular type of computer/device/platform // portable
language
• A language such as Python, Java, Pascal, etc. (any suitable example)
2
2(b)
One from:
• Compiler
• Interpreter
1
2(c)
Must relate to answer given in 2b. No follow through for incorrect answer in
part 2b.
3
Compiler – Three from:
• Translates the whole program as a complete unit / at once
• Creates an executable file / object code
• A report / list of errors in the code is created
• Optimises the source code (to run efficiently)
Interpreter – Three from:
• Translates a program one line of code at a time
• Machine code is directly executed // The interpreter is used each time
the program / code is executed
• Will identify an error as soon as it finds one in a line of code
© UCLES 2017
Page 2 of 8
Marks
0478/11
Question
3
May/June 2017
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
1 mark per correct tick
4
Statement
true
(9)
false
(9)
9
47KB is larger than 10MB.
250bytes is smaller than 0.5MB.
9
50GB is larger than 100MB.
9
9
1TB is smaller than 4GB.
Question
4
Answer
1 mark per correct tick
5
Statement
True
False
Data is transmitted in one direction only, one
bit at a time.
9
Data is transmitted in both directions,
multiple bits at a time.
9
Data is transmitted in one direction only,
multiple bits at a time.
9
Data is transmitted in both directions, but
only one direction at a time. Data is
transmitted one bit at a time.
Data is transmitted in both directions, but
only one direction at a time. Data is
transmitted multiple bits at a time.
© UCLES 2017
Marks
Page 3 of 8
9
9
0478/11
Question
5(a)
May/June 2017
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
1 mark per correct tick
Received byte
3
corrupted
during
transmission
(9)
not corrupted
during
transmission
(9)
9
10110100
9
01101101
9
10000001
5(b)
Four from:
• Uses acknowledgement and time out
• Check performed on received data // error is detected by e.g. parity
check, check sum
• If error detected, request sent to resend data // negative
acknowledgment is used
• If no acknowledgement is sent that data is received // positive
acknowledgement is used
• Data is resent / Resend request repeated, till data is resent correctly «
• « or request times out // limit is reached
Question
Answer
6
1 mark for correct bus name and up to 2 further marks for appropriate
purpose.
Address (bus)
Two from:
• Carries / transports an address / location «
• « of the next item to be fetched
• Data travels one way (unidirectional)
Data (bus)
Two from:
• Carries / transports data / example of data ...
• « that is currently being processed // that will be / has been processed
• Data can travel in both directions (bidirectional)
Control (bus)
Two from:
• Carries / transports signals
• Control / directs the actions of the CPU / processor
• Can be either Unidirectional or Bidirectional
© UCLES 2017
Page 4 of 8
4
Marks
6
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
7
May/June 2017
Marks
5
1 mark for correct line till 5 marks given.
Question
8
© UCLES 2017
Answer
•
•
•
•
•
•
Marks
6
Secondary
HDD/SSD
SSD/HDD
Primary
ROM/RAM
RAM/ROM
Page 5 of 8
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
9
Answer
May/June 2017
Marks
1 mark for appropriate device name and 1 further mark for appropriate
purpose.
6
Input devices
Two from:
• Keypad / Keyboard «
• « e.g. to allow customer to input the quantity of an item
• Touchscreen «
• « e.g. to allow a customer to select a payment method
• Barcode scanner / Barcode reader «
• « e.g. to allow a customer to scan in their shopping
• Card reader // Cash deposit / intake «
• « e.g. to allow a customer to pay for their shopping
• Weighing scales «
• « e.g. to allow a customer to weigh fresh produce
Output devices
One from:
• Display / Touchscreen «
• « e.g. to allow a customer to see the running total of their shopping
• Speaker «
• « e.g. to give audio instructions to a customer about how to use the
self-checkout
• Printer «
• « e.g. to print a receipt for the customer
Question
10(a)
10(b)
Answer
1 mark for four correct outputs only
1
A
B
Output
0
0
1
0
1
0
1
0
0
1
1
0
1 mark for each correct section of the statement
•
•
•
© UCLES 2017
Marks
(A AND B)
AND
(C OR NOT B)
Page 6 of 8
3
0478/11
Question
11
Question
12(a)
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2017
Answer
Three from e.g. :
• (Provides an) interface
• Loads / opens / installs / closes software
• Manages the hardware // manages peripherals // spooling
• Manages the transfer of programs into and out of memory
• Divides processing time // processor management
• Manages file handling
• Manages error handling // manages interrupts
• Manages security software
• Manages utility software
• Manages user accounts
• Multitasking
• Multiprogramming // time slicing
• Batch processing
Answer
1 mark for appropriate sensor and 1 further mark for appropriate use.
Marks
3
Marks
4
Two from:
• Gas (sensor) «
• « e.g. to measure the levels of oxygen/carbon dioxide / nitrogen in the
factory to make sure they are not too high / low
• Temperature (sensor) «
• « e.g. to measure the temperature of the chemicals to make sure it is
not too high/low
• Motion / Infra-red (sensor) «
• « e.g. to detect any persons in an unauthorised area of the factory
• Pressure (sensor) «
• « e.g. to measure the pressure of chemicals flowing through pipes to
check that level are not too high / low
• pH (sensor) «
• « to measure the pH to make sure the acidity / alkalinity of the
chemicals is correct
• Light (sensor) «
• « to measure the level of light to make sure it remains at a constant
level for the chemical process
12(b)
© UCLES 2017
Five from:
• Sensors send signals to microprocessor
• Analogue signals are converted to digital (using ADC)
• Microprocessor compares value to stored value «
• « If out of range / matches stored values «
• « signal sent to alert workers (e.g. sound alarm)
• « microprocessor send signal to cause an action to occur e.g. cool a
process down, heat a process up, add a chemical
• « no action taken
• Output/record readings
• Monitoring is continuous
Page 7 of 8
5
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
13(a)
13(b)(i)
Answer
2
•
•
Lossless (compression) «
« It is important the code must be (exactly) the same as the original
file
« If it does not match the original file it will not work
3
Lossy (compression) «
« It would make the file smaller than lossless compression / the file
would stream faster than lossless compression
« The quality of the video can be reduced but it can still be viewed
3
•
•
•
© UCLES 2017
Marks
Two from:
• Smaller file to transmit
• The file is transmitted quicker
• Uses / requires less bandwidth
•
13(b)(ii)
May/June 2017
Page 8 of 8
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 4 5 7 2 4 7 7 1 5 8 *
0478/12
COMPUTER SCIENCE
May/June 2017
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
DC (CW/JG) 134134/3
© UCLES 2017
[Turn over
2
1
Name three different buses that are used in the fetch-execute cycle.
Bus 1 ������������������������������������������������������������������������������������������������������������������������������������������������
Bus 2 ������������������������������������������������������������������������������������������������������������������������������������������������
Bus 3 ������������������������������������������������������������������������������������������������������������������������������������������������
[3]
2
Give two examples of primary, secondary and off-line storage.
Primary
Example 1 ����������������������������������������������������������������������������������������������������������������������������������������
Example 2 ����������������������������������������������������������������������������������������������������������������������������������������
Secondary
Example 1 ����������������������������������������������������������������������������������������������������������������������������������������
Example 2 ����������������������������������������������������������������������������������������������������������������������������������������
Off-line
Example 1 ����������������������������������������������������������������������������������������������������������������������������������������
Example 2 ����������������������������������������������������������������������������������������������������������������������������������������
[6]
© UCLES 2017
0478/12/M/J/17
3
3
The diagram shows five output devices and five descriptions.
Draw a line between each output device and its description.
Output Device
Description
Inkjet printer
Flat panel display that uses the light modulating
properties of liquid crystals.
LCD screen
Flat panel display that uses an array of
light‑emitting diodes as pixels.
2D cutter
Droplets of ink are propelled onto paper.
LED screen
Electrically charged powdered ink is transferred
onto paper.
Laser printer
High powered laser that uses the x-y plane.
[4]
© UCLES 2017
0478/12/M/J/17
[Turn over
4
4
There are various methods used to detect errors that can occur during data transmission and
storage.
Describe each of the following error detection methods.
Parity check �������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
Check digit ���������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
Checksum ����������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
Automatic Repeat request (ARQ) ����������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
[8]
© UCLES 2017
0478/12/M/J/17
5
5
(a) The denary number 57 is to be stored in two different computer registers.
Convert 57 from denary to binary and show your working.
���������������������������������������������������������������������������������������������������������������������������������������������������
���������������������������������������������������������������������������������������������������������������������������������������������������
���������������������������������������������������������������������������������������������������������������������������������������������������
�����������������������������������������������������������������������������������������������������������������������������������������������[2]
(b) Show the binary number from part (a) as it would be stored in the following registers.
Register 1
Register 2
[2]
(c) A binary number stored in a register can have many different uses, for example an address in
main memory.
Give two other uses for a binary number stored in a register.
Use 1 ����������������������������������������������������������������������������������������������������������������������������������������
Use 2 ����������������������������������������������������������������������������������������������������������������������������������������
[2]
(d) A register in a computer contains binary digits.
0
0
1
1
1
0
1
0
The contents of the register represent a binary integer.
Convert the binary integer to hexadecimal.
....................................................................................................................................................
................................................................................................................................................[1]
© UCLES 2017
0478/12/M/J/17
[Turn over
6
6
Airline boarding passes can be read from a smartphone instead of a printout.
Back
Boarding Pass
A
TSA Pre
Passenger Webb / Alan
B 15
Boarding
Boarding
Position
Group
Flight 683
JFK – LAX
Date
Thursday, November 10, 2016
Departs 8.15 pm
Gate
C4
Time, gate and terminals may change - check monitors
Fly Rewards
Fly Rewards# 12345678
Conf# BC123D
Identify what type of barcode A is an example of. Explain how the data stored in this type of
barcode is read.
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
����������������������������������������������������������������������������������������������������������������������������������������������������������
������������������������������������������������������������������������������������������������������������������������������������������������������[4]
© UCLES 2017
0478/12/M/J/17
7
7
Computer A is communicating with computer B.
(a) Draw an arrow or arrows to show simplex, duplex and half-duplex data transmission. The
direction of the data transmission must be fully labelled.
Simplex data transmission
Computer A
Computer B
Duplex data transmission
Computer A
Computer B
Half-duplex data transmission
Computer A
Computer B
[6]
(b) State a use for the following data transmission methods. The use must be different for each
data transmission method.
Simplex �������������������������������������������������������������������������������������������������������������������������������������
���������������������������������������������������������������������������������������������������������������������������������������������������
Duplex ��������������������������������������������������������������������������������������������������������������������������������������
���������������������������������������������������������������������������������������������������������������������������������������������������
[2]
© UCLES 2017
0478/12/M/J/17
[Turn over
8
(c) A computer includes an Integrated Circuit (IC) and a Universal Serial Bus (USB) for data
transmission.
Describe how the computer uses these for data transmission, including the type of data
transmission used.
IC ����������������������������������������������������������������������������������������������������������������������������������������������
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USB ������������������������������������������������������������������������������������������������������������������������������������������
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[4]
© UCLES 2017
0478/12/M/J/17
9
8
A company has a number of offices around the world.
(a) Data is transmitted between the offices over the Internet. In order to keep the data safe the
company is using Secure Socket Layer (SSL) protocol and a firewall at each office.
Explain how SSL protocol and a firewall will keep the company’s data safe.
SSL protocol �����������������������������������������������������������������������������������������������������������������������������
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Firewall �������������������������������������������������������������������������������������������������������������������������������������
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[4]
(b) A company stores personal details of its customers on a computer system behind a firewall.
Explain, with reasons, what else the company should do to keep this data safe.
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© UCLES 2017
0478/12/M/J/17
[Turn over
10
9
A cold store is kept at a constant low temperature using a sensor, a microprocessor and a cooling
unit.
Explain how the sensor and microprocessor will maintain a constant low temperature.
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© UCLES 2017
0478/12/M/J/17
11
10 For this logic statement:
X = 1 if (( A is 1 AND B is 1 ) OR ( B is 1 AND C is NOT 1 ))
(a) Draw the logic circuit.
A
B
X
C
[4]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2017
0478/12/M/J/17
[Turn over
12
11
A company sells smartphones over the Internet.
Explain how the information stored on the company’s website is requested by the customer, sent
to the customer’s computer and displayed on the screen.
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017
0478/12/M/J/17
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
Paper 1
May/June 2017
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2017 series for most Cambridge IGCSE®,
Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level
components.
® IGCSE is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 9 printed pages.
© UCLES 2017
[Turn over
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
•
•
•
2
Marks
3
address (bus)
control (bus)
data (bus)
Question
May/June 2017
Answer
2 marks for each type of storage
Marks
6
Primary storage
• RAM
• ROM
Secondary storage
• hard disk drive (HDD)
• solid state drive (SSD)
Off-line storage e.g.
• CD
• DVD
• Blu-ray
• Flash memory // USB storage
• removable / external / portable hard disk drive (HDD/SSD)
• SD card
Question
Answer
3
4
1 mark for each correct line to a max of 4 marks.
© UCLES 2017
Marks
Page 2 of 9
0478/12
Question
4
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2017
Answer
Two marks for each correct description
Parity Check
• Checks a byte of data
• Check is performed when data is received
• A parity bit is added (to the parity byte)
• Counts / checks number of 1’s // counts / checks to see if 1’s are even
// counts / checks to see if 1’s are odd
• Can be even or odd
• If parity is incorrect, error is detected
Check digit
• A digit that is calculated from the data // uses modulo to calculate digit
// valid description of modulo
• It is appended / added to the data
• Digit is recalculated when data is entered
• Digits are compared to check for error
Checksum
• A value is calculated from the data // Valid description of calculation
• It is transmitted with the data
• Value is recalculated after transmission
• Values are compared after transmission to check for error
Automatic Repeat reQuest
• Uses acknowledgement / request and time-out
• Error control protocol
• Check performed on receiving data // error is detected by e.g. parity
check, check sum
• If error detected, request is sent to resend data // negative
acknowledgement is used
• Resend request is repeated till data is sent correctly / requests time
out / limit is reached
• Send acknowledgement that data is received // positive
acknowledgement is used
• If acknowledgement not received in set time data is resent
© UCLES 2017
Page 3 of 9
Marks
8
0478/12
Question
5(a)
May/June 2017
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
1 mark for correct method, 1 mark for correct answer
2
32 + 16 + 8 + 1
(00)111001
5(b)
registers must have leading zeros, allow follow through from 5(a) for an
incorrect value
1 mark for each correct register.
0
0
0
5(c)
0
0
0
1
0
0
0
0
0
0
1
0
1
1
1
0
0
data
ASCII value / Unicode value / character
number
part of image / small image
a sound / sound sample / small sound track
instruction
1
Answer
1 mark for correct name of code, up to a further 3 marks for appropriate
explanation
•
Quick response (QR) Code
Three from:
• Barcode is captured / scanned / imaged, by a camera / scanner /
barcode reader / QR code reader
• Read using a laser
• Processed by an app
• Light is reflected back
• Black squares reflect less light than white squares
• Modules are used for orientation / alignment
• Squares / data are decoded
© UCLES 2017
1
2
3A
Question
6
0
1
Two from:
•
•
•
•
•
•
5(d)
1
2
Page 4 of 9
Marks
4
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7(a)
May/June 2017
Answer
1 mark for correct arrow(s), one mark for correct description
OR
(Direction of data is) one way only // unidirectional
#
(Direction of data is both ways) at same time / simultaneously / concurrently
AND
(Direction of data is both ways) but at different times / not at the same time /
not simultaneously / not concurrently
© UCLES 2017
Page 5 of 9
Marks
6
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7(b)
May/June 2017
Answer
1 mark each use, must be different.
Marks
2
Simplex e.g.:
Microphone to computer
Sensor to computer
Computer to printer
Computer to speaker
Computer to monitor
Webcam to computer
Sending data to a device // sending data from a device
Duplex e.g.:
Telephone call
Voice over IP
Computer to printer (only award once)
Instant messaging
Broadband connections
Video conferencing
Sending data to and from devices e.g wireless technology
Computer to modem
7(c)
2 marks for IC, 2 marks for USB
IC
•
•
USB
•
•
Question
8(a)
4
parallel transmission // description of parallel
for sending data internally
serial transmission // description of serial
for sending data externally (to and from peripherals / between
devices)
Answer
2 marks for SSL, 2 marks for Firewall
SSL protocol
Two from:
• uses encryption
• encryption is asymmetric / symmetric / both
• makes use of (public and private) keys
• data is meaningless (without decryption key / if intercepted)
Firewall
Two from:
• helps prevent unauthorised access // helps prevent hacking
• checks that data meets criteria // identifies when data does not meet
criteria
• acts as a filter for (incoming and outgoing) data // blocks any
unacceptable data //allows acceptable data through
© UCLES 2017
Page 6 of 9
Marks
4
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8(b)
May/June 2017
Answer
Six from:
Marks
6
Encrypt the data «
« so it cannot be understood by those not entitled to view it
Password protected / biometrics «
« to help prevent unauthorised access
Virus checking software «
« helps prevent data corruption or deletion
« identifies / removes a virus in the system
« scans a system for viruses
Spyware checking software «
« helps prevent data being stolen/copied/logged
« scans a system for spyware
Drop-down input methods / selectable features «
« to reduce risk of spyware / keylogging
Physical method e.g. locked doors / CCTV timeout / auto log off
« to help prevent unauthorised access
Network / company policies // training employees
« to educate users how to be vigilant
Access rights «
« allows users access to data that they have permission to view
« prevents users from accessing data that they do not have permission to
view
Question
9
Answer
Six from:
•
•
•
•
•
•
•
•
•
•
© UCLES 2017
Marks
6
temperature sensor
analogue data / temperature is converted to digital data (with an ADC)
sensor sends signal to the microprocessor
microprocessor compares input values with stored values/pre-set
values «
« if the temperature value input is too high/low «
« a signal is sent from the microprocessor to turn on / off / up / down
the cooling unit
« if temperature matches the stored values «
« no action is taken
an actuator is used to turn the cooling unit on / off / up / down
the process is a continuous loop
Page 7 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
10(a)
Answer
Marks
1 mark for each correct gate, with the correct input(s)
10(b)
4
4
A
B
C
X
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
1
1
1
1
1
4 marks for 8 correct outputs
3 marks for 6 or 7 correct outputs
2 marks for 4 or 5 correct outputs
1 mark for 2 or 3 correct outputs
© UCLES 2017
May/June 2017
Page 8 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
11
May/June 2017
Answer
Seven from:
7
Requested
• a web browser is used
• user enters the URL / web address (into the address bar) // clicks a
link containing the web address // clicks an element of the webpage
• the URL / web address specifies the protocol
• protocols used are Hyper Text Transfer Protocol (HTTP) / Hyper Text
Transfer Protocol Secure (HTTPS)
Sent
•
•
•
•
•
the URL / web address contains the domain name
the Internet Service Provider (ISP) looks up the IP address of the
company
the domain name is used to look up the IP address of the company
the domain name server (DNS) stores an index of domain names and
IP addresses
web browser sends a request to the web server / IP address
Received
• Data for the website is stored on the company’s web server
• webserver sends the data for the website back to the web browser
• web server uses the customer’s IP address to return the data
• the data is transferred into Hyper Text Mark-up Language (HTML)
• HTML is interpreted by the web browser (to display the website)
© UCLES 2017
Marks
Page 9 of 9
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 2 4 9 9 6 2 0 5 5 8 *
0478/13
COMPUTER SCIENCE
May/June 2017
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
DC (KN/SG) 144781
© UCLES 2017
[Turn over
2
1
The memory of a computer contains data and instructions in binary.
The following instruction is stored in a location of the memory.
0
0
1
0
1
0
0
1
1
1
1
1
1
1
0
0
(a) Convert the instruction into hexadecimal.
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................... [2]
(b) Explain why a programmer might prefer to read the instruction in hexadecimal rather than in
binary.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................... [2]
(c) Give two other uses of hexadecimal.
Use 1 ........................................................................................................................................
...................................................................................................................................................
Use 2 ........................................................................................................................................
...................................................................................................................................................
[2]
2
Programmers can use a high-level language to write a computer program.
(a) Explain what is meant by the term ‘high-level language’.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2017
0478/13/M/J/17
3
(b) A program written in a high-level language is translated into machine code. This is so that it
can be processed by a computer.
Name one type of translator that can be used.
.............................................................................................................................................. [1]
(c) Describe how your answer to part (b) translates this program.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [3]
3
Steffi has a number of files of different sizes that contain her work.
Tick (3) to show whether each statement is true or false.
true
(3)
Statement
false
(3)
47KB is larger than 10MB.
250bytes is smaller than 0.5MB.
50GB is larger than 100MB.
1TB is smaller than 4GB.
[4]
© UCLES 2017
0478/13/M/J/17
[Turn over
4
4
Five statements about serial half-duplex data transmission are shown in the table below.
Tick (3) to show whether each statement is true or false.
Statement
true
(3)
false
(3)
Data is transmitted in one direction only, one bit at a time.
Data is transmitted in both directions, multiple bits at a time.
Data is transmitted in one direction only, multiple bits at a time.
Data is transmitted in both directions, but only one direction at a
time. Data is transmitted one bit at a time.
Data is transmitted in both directions, but only one direction at a
time. Data is transmitted multiple bits at a time.
© UCLES 2017
0478/13/M/J/17
[5]
5
5
(a) Parity checks are often used to detect errors that may occur during data transmission.
The received bytes in the table below were transmitted using odd parity.
Tick (3) to show whether each byte has been corrupted during transmission or not
corrupted during transmission.
Received byte
corrupted
during
transmission
(3)
not corrupted
during
transmission
(3)
10110100
01101101
10000001
[3]
(b) Another method of error detection is Automatic Repeat reQuest (ARQ).
Explain how ARQ is used in error detection.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2017
0478/13/M/J/17
[Turn over
6
6
Signals are sent to and from the components of a processor using buses.
Identify and describe the purpose of two different buses.
Bus 1 ....................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Bus 2 ....................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2017
0478/13/M/J/17
7
7
Six security terms and six statements are listed below.
Draw a line to match the security term with the most appropriate statement.
Security term
Statement
Encryption
Provides a secure connection between
web browsers and websites allowing
secure transmission of private data.
Secure Socket
Layer (SSL)
Computer that acts as an intermediary
between a web browser and the
Internet.
Pharming
Legitimate-looking email is sent in the
hope of gathering personal information;
it requires the user to click on a link in
the email.
Phishing
Uses rules and criteria, set by the user,
to help protect a network or system from
unauthorised access.
Firewall
Malicious code installed on the hard
drive of a user’s computer; this code
will redirect the user to a fake website
without the user’s knowledge.
Proxy server
Scrambles data for secure transmission.
[5]
© UCLES 2017
0478/13/M/J/17
[Turn over
8
8
Complete the paragraph by choosing six correct terms from the list.
•
•
•
•
•
•
•
•
•
Optical
On-line
RAM
HDD
Primary
SSD
Secondary
ROM
Off-line
A computer has two different types of memory. .................................... memory is not directly
accessed by the CPU, but it allows a user to store data that can easily be accessed by applications.
Two examples of this type of memory are .................................... and .................................... . The
second type of memory is .................................... memory. This memory is directly accessed by
the CPU. It allows the processor to access data and instructions that are stored in this memory.
Two examples of this memory are .................................... and .................................... .
© UCLES 2017
0478/13/M/J/17
[6]
9
9
A supermarket has a system that allows customers to check out their own shopping.
Identify and describe the purpose of two input devices and one output device used in this system.
Input device 1 ...................................................................................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Input device 2 ...................................................................................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Output device 1 ................................................................................................................................
Purpose ............................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
10 (a) Complete the truth table for the NOR gate.
A
X
B
A
B
0
0
0
1
1
0
1
1
Output (X)
[1]
© UCLES 2017
0478/13/M/J/17
[Turn over
10
(b) Write a logic statement that corresponds with the following logic circuit.
A
B
X
C
X = ..................................................................................................................................... [3]
11
State three functions provided by an operating system.
Function 1 ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Function 2 ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Function 3 ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[3]
© UCLES 2017
0478/13/M/J/17
11
12 The processes in a chemical factory are monitored by sensors connected to a microprocessor.
(a) Identify two different sensors used in this application. Give an example of how each sensor
could be used in the chemical factory.
Sensor 1 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
Sensor 2 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
[4]
(b) Describe how the sensors and a microprocessor are used to monitor a process.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [5]
© UCLES 2017
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[Turn over
12
13 (a) Gurdeep wants to send a large file to Jennifer over the Internet.
State two benefits of compressing the file to send it.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(b) Two types of compression are lossy and lossless.
Choose the most suitable type of compression for the following and explain your choice.
(i)
Downloading the code for a computer program:
Type of compression .........................................................................................................
Explanation .......................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
(ii)
Streaming a video file:
Type of compression .........................................................................................................
Explanation .......................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017
0478/13/M/J/17
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
Paper 1
May/June 2017
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge will not enter into discussions about these mark schemes.
Cambridge is publishing the mark schemes for the May/June 2017 series for most Cambridge IGCSE®,
Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level
components.
® IGCSE is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 8 printed pages.
© UCLES 2017
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
May/June 2017
Answer
Marks
1(a)
1 mark for any two correct values, 2 marks for all 4 correct values.
29FC
2
1(b)
Two from:
• Easier/quicker to understand/read
• Easier to debug/identify errors
• Fewer digits are used / shorter // takes up less space on screen // more
can be shown on screen / page
2
1(c)
Two from:
• Notations for colour in HTML // HTML colour (codes)
• Error messages
• MAC address // IP address
• Locations in memory
• Memory dump
2
Question
Answer
2(a)
Two from:
• Closer to human language // closer to English
• Independent of a particular type of computer/device/platform // portable
language
• A language such as Python, Java, Pascal, etc. (any suitable example)
2
2(b)
One from:
• Compiler
• Interpreter
1
2(c)
Must relate to answer given in 2b. No follow through for incorrect answer in
part 2b.
3
Compiler – Three from:
• Translates the whole program as a complete unit / at once
• Creates an executable file / object code
• A report / list of errors in the code is created
• Optimises the source code (to run efficiently)
Interpreter – Three from:
• Translates a program one line of code at a time
• Machine code is directly executed // The interpreter is used each time
the program / code is executed
• Will identify an error as soon as it finds one in a line of code
© UCLES 2017
Page 2 of 8
Marks
0478/13
Question
3
May/June 2017
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
1 mark per correct tick
4
Statement
true
(9)
false
(9)
9
47KB is larger than 10MB.
250bytes is smaller than 0.5MB.
9
50GB is larger than 100MB.
9
9
1TB is smaller than 4GB.
Question
4
Answer
1 mark per correct tick
5
Statement
True
False
Data is transmitted in one direction only, one
bit at a time.
9
Data is transmitted in both directions,
multiple bits at a time.
9
Data is transmitted in one direction only,
multiple bits at a time.
9
Data is transmitted in both directions, but
only one direction at a time. Data is
transmitted one bit at a time.
Data is transmitted in both directions, but
only one direction at a time. Data is
transmitted multiple bits at a time.
© UCLES 2017
Marks
Page 3 of 8
9
9
0478/13
Question
5(a)
May/June 2017
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
1 mark per correct tick
Received byte
3
corrupted
during
transmission
(9)
not corrupted
during
transmission
(9)
9
10110100
9
01101101
9
10000001
5(b)
Four from:
• Uses acknowledgement and time out
• Check performed on received data // error is detected by e.g. parity
check, check sum
• If error detected, request sent to resend data // negative
acknowledgment is used
• If no acknowledgement is sent that data is received // positive
acknowledgement is used
• Data is resent / Resend request repeated, till data is resent correctly «
• « or request times out // limit is reached
Question
Answer
6
1 mark for correct bus name and up to 2 further marks for appropriate
purpose.
Address (bus)
Two from:
• Carries / transports an address / location «
• « of the next item to be fetched
• Data travels one way (unidirectional)
Data (bus)
Two from:
• Carries / transports data / example of data ...
• « that is currently being processed // that will be / has been processed
• Data can travel in both directions (bidirectional)
Control (bus)
Two from:
• Carries / transports signals
• Control / directs the actions of the CPU / processor
• Can be either Unidirectional or Bidirectional
© UCLES 2017
Page 4 of 8
4
Marks
6
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
7
May/June 2017
Marks
5
1 mark for correct line till 5 marks given.
Question
8
© UCLES 2017
Answer
•
•
•
•
•
•
Marks
6
Secondary
HDD/SSD
SSD/HDD
Primary
ROM/RAM
RAM/ROM
Page 5 of 8
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
9
Answer
May/June 2017
Marks
1 mark for appropriate device name and 1 further mark for appropriate
purpose.
6
Input devices
Two from:
• Keypad / Keyboard «
• « e.g. to allow customer to input the quantity of an item
• Touchscreen «
• « e.g. to allow a customer to select a payment method
• Barcode scanner / Barcode reader «
• « e.g. to allow a customer to scan in their shopping
• Card reader // Cash deposit / intake «
• « e.g. to allow a customer to pay for their shopping
• Weighing scales «
• « e.g. to allow a customer to weigh fresh produce
Output devices
One from:
• Display / Touchscreen «
• « e.g. to allow a customer to see the running total of their shopping
• Speaker «
• « e.g. to give audio instructions to a customer about how to use the
self-checkout
• Printer «
• « e.g. to print a receipt for the customer
Question
10(a)
10(b)
Answer
1 mark for four correct outputs only
1
A
B
Output
0
0
1
0
1
0
1
0
0
1
1
0
1 mark for each correct section of the statement
•
•
•
© UCLES 2017
Marks
(A AND B)
AND
(C OR NOT B)
Page 6 of 8
3
0478/13
Question
11
Question
12(a)
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2017
Answer
Three from e.g. :
• (Provides an) interface
• Loads / opens / installs / closes software
• Manages the hardware // manages peripherals // spooling
• Manages the transfer of programs into and out of memory
• Divides processing time // processor management
• Manages file handling
• Manages error handling // manages interrupts
• Manages security software
• Manages utility software
• Manages user accounts
• Multitasking
• Multiprogramming // time slicing
• Batch processing
Answer
1 mark for appropriate sensor and 1 further mark for appropriate use.
Marks
3
Marks
4
Two from:
• Gas (sensor) «
• « e.g. to measure the levels of oxygen/carbon dioxide / nitrogen in the
factory to make sure they are not too high / low
• Temperature (sensor) «
• « e.g. to measure the temperature of the chemicals to make sure it is
not too high/low
• Motion / Infra-red (sensor) «
• « e.g. to detect any persons in an unauthorised area of the factory
• Pressure (sensor) «
• « e.g. to measure the pressure of chemicals flowing through pipes to
check that level are not too high / low
• pH (sensor) «
• « to measure the pH to make sure the acidity / alkalinity of the
chemicals is correct
• Light (sensor) «
• « to measure the level of light to make sure it remains at a constant
level for the chemical process
12(b)
© UCLES 2017
Five from:
• Sensors send signals to microprocessor
• Analogue signals are converted to digital (using ADC)
• Microprocessor compares value to stored value «
• « If out of range / matches stored values «
• « signal sent to alert workers (e.g. sound alarm)
• « microprocessor send signal to cause an action to occur e.g. cool a
process down, heat a process up, add a chemical
• « no action taken
• Output/record readings
• Monitoring is continuous
Page 7 of 8
5
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
13(a)
13(b)(i)
Answer
2
•
•
Lossless (compression) «
« It is important the code must be (exactly) the same as the original
file
« If it does not match the original file it will not work
3
Lossy (compression) «
« It would make the file smaller than lossless compression / the file
would stream faster than lossless compression
« The quality of the video can be reduced but it can still be viewed
3
•
•
•
© UCLES 2017
Marks
Two from:
• Smaller file to transmit
• The file is transmitted quicker
• Uses / requires less bandwidth
•
13(b)(ii)
May/June 2017
Page 8 of 8
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 1 3 2 0 9 6 4 5 0 9 *
0478/11
COMPUTER SCIENCE
October/November 2017
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (NH/SW) 134256/4
© UCLES 2017
[Turn over
2
1
A washing machine has a small display screen built into it.
One use of the display screen is to show an error code when a problem has occurred with a
washing cycle.
(a) State whether the display screen is an input, output or storage device.
...............................................................................................................................................[1]
(b) The display screen shows a hexadecimal error code:
E04
This error code means that the water will not empty out of the washing machine.
Convert this error code to binary.
[3]
(c) State why hexadecimal is used to display the error code.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[1]
(d) Identify three sensors that could be used in the washing machine.
State what each sensor could be used for.
Sensor 1 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
Sensor 2 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
Sensor 3 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2017
0478/11/O/N/17
3
2
Data files are stored in different file formats.
Complete the table by providing a suitable file format for each file type. The first one has been
done for you.
File type
Pictures
File format
.JPEG
Text
Sound
Video
[3]
3
(a) An example of a Uniform Resource Locator (URL) is:
http://www.cie.org.uk/index.htm
Part 1
Part 2
Part 3
Identify the three parts that make up this URL.
Part 1 ........................................................................................................................................
Part 2 ........................................................................................................................................
Part 3 ........................................................................................................................................
[3]
(b) Describe what is meant by an Internet Protocol (IP) address.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
© UCLES 2017
0478/11/O/N/17
[Turn over
4
4
Six components of a computer system and six descriptions are shown.
Draw a line to match each component with the most suitable description.
Component
Description
Arithmetic Logic
Unit (ALU)
Used to connect together
the internal components
of the CPU.
Buses
Used to carry out
calculations on data.
Control Unit
(CU)
Used to temporarily hold
data and instructions
during processing.
Immediate Access
Store (IAS)
Used to allow interaction
with the computer.
Input/Output
Used to hold data and
instructions before they
are processed.
Registers
Used to manage the flow
of data through the CPU.
[5]
© UCLES 2017
0478/11/O/N/17
5
5
(a) Draw a logic circuit for the logic statement:
X = 1 if ((A is 1 AND B is 1) OR (A is NOT 1 AND C is 1))
A
X
B
C
[4]
© UCLES 2017
0478/11/O/N/17
[Turn over
6
(b) Draw the symbol for an XOR gate and explain the function of this logic gate.
Explanation ...............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[5]
6
Describe the operation of a 2D scanner and a 3D scanner.
2D .....................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
3D .....................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2017
0478/11/O/N/17
7
7
Six statements about firewalls are shown.
Tick (3) to show whether each statement is true or false.
Statement
true
(3)
false
(3)
Firewalls can monitor incoming and
outgoing traffic.
Firewalls operate by checking traffic against
a set of rules.
Firewalls cannot block access to a certain
website.
Firewalls can be software and hardware.
Firewalls can act as intermediary servers.
Firewalls can block unauthorised traffic.
[6]
© UCLES 2017
0478/11/O/N/17
[Turn over
8
8
(a) Data is valuable. It needs to be kept secure and it can easily be damaged.
Give three different ways that data can be accidentally damaged.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
3 ................................................................................................................................................
...................................................................................................................................................
[3]
(b) The Secure Socket Layer (SSL) protocol can be used to securely transmit data in online
banking.
State three other different applications that use SSL.
Application 1 .............................................................................................................................
Application 2 .............................................................................................................................
Application 3 .............................................................................................................................
[3]
© UCLES 2017
0478/11/O/N/17
9
(c) Online banking is increasing in popularity.
Online banking can be a risk as it can raise a number of security issues. SSL can be used as
a security method to make online banking safer.
Identify and describe three other security methods that could be used to make online banking
safer.
Security method 1 .....................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Security method 2 .....................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Security method 3 .....................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2017
0478/11/O/N/17
[Turn over
10
9
(a) Optical storage media can be used to store data.
Describe how the data is read from a Compact Disc (CD).
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
(b) Kamil wants to store a 16-bit colour image file. The image size is 1000 pixels.
Calculate the size of the file.
Give your answer in bytes. Show your working.
Working .....................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Answer ............................... bytes
[2]
(c) Describe the differences between primary and secondary storage.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
© UCLES 2017
0478/11/O/N/17
11
10 Six statements about assembly language are shown.
Tick (3) whether the statement is true or false.
Statement
true
(3)
false
(3)
Assembly language uses mnemonic codes.
Assembly language programs do not need
a translator to be executed.
Assembly language is a low-level
programming language.
Assembly language is specific to the
computer hardware.
Assembly language is machine code.
Assembly language is often used to create
drivers for hardware.
[6]
© UCLES 2017
0478/11/O/N/17
12
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017
0478/11/O/N/17
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
Paper 1
October/November 2017
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2017 series for most
Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level
components.
® IGCSE is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 10 printed pages.
© UCLES 2017
[Turn over
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November
2017
Marks
1(a)
Output
1
1(b)
1 mark for each correct conversion
3
E
1
1
0
1
0
0
0
4
0
0
0
1
0
0
1(c)
Any one from:
– Hexadecimal codes can fit in a smaller display rather than a full text based message
– Smaller amount of memory needed to store the hex error messages than text based
1
1(d)
1 mark for correct sensor, 1 mark for corresponding use
Possible examples could include:
6
© UCLES 2017
–
–
Temperature (sensor)
To monitor the temperature of the water
–
–
Pressure (sensor)
To monitor the level of water in the washing machine
–
–
Motion (sensor)
To monitor whether the drum is still in motion
–
–
pH (sensor)
To monitor the level of water hardness/detergent present in the water
Page 2 of 10
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2
Answer
1 mark for each correct file format e.g.
3(a)
3(b)
© UCLES 2017
File format
Pictures
.JPEG
Text
.doc, .txt, .rtf,
.docx, .odt .pdf
Sound
.mp3, .wav, .aif,
.flac, .mid
Video
.mp4, .flv, .wmv
Answer
–
–
–
Part 1
Part 2
Part 3
Marks
3
File type
Question
October/November
2017
(access) protocol
domain (name)
filename
Marks
3
Four from:
– IP address is used to identify a device (on the Internet / network)
– IP address is allocated by the network/ ISP
– Can be used in place of URL
– IP addresses can be IPv4 or IPv6
– IP address can be static «
– ... meaning it doesn’t change each time it is connected to the Internet
– IP address can be dynamic «.
– « meaning that it can change each time a device is connected to the Internet
– Any valid example (e.g. xxx.xxx.xxx.xxx or xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx)
Page 3 of 10
4
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4
© UCLES 2017
Answer
1 mark for each correct line up to a total of 5 marks
October/November
2017
Marks
5
Page 4 of 10
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(a)
© UCLES 2017
Answer
1 mark for each correct logic gate
October/November
2017
Marks
4
Page 5 of 10
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(b)
Answer
1 mark for correct logic gate symbol:
October/November
2017
Marks
5
Any four from:
– similar to an OR gate
– It has (at least) two inputs
– Output will be high/1 if both inputs are different
– Output will be high/1 if either input is high
– Output will be low/0 if both inputs are high
– Output will be low/0 if both inputs are low
Question
6
© UCLES 2017
Answer
Any six from:
Marks
6
–
–
–
–
–
2D
(Scanner) shines a light onto the surface of a document // Light moves across document
Reflected light is captured
Uses mirrors and lenses
Captured image is converted into a digital file
Produces a 2D digital image
–
–
–
–
3D
Scanners shines a laser (or light) over the surface of a 3D object
Records measurements of the geometry/dimensions of the object
Measurements are converted to digital file
Produces a 3D digital model
Page 6 of 10
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7
October/November
2017
Answer
Marks
1 mark for each correct tick
6
true
(9)
Statement
Firewalls can monitor incoming and outgoing traffic.
9
Firewalls operate by checking traffic against a set of rules.
9
9
Firewalls cannot block access to a certain website.
9
Firewalls can be software and hardware.
9
Firewalls can act as intermediary servers.
9
Firewalls can block unauthorised traffic.
Question
false
(9)
Answer
Marks
8(a)
Any three from:
– Human error (e.g. deleting/overwriting data)
– Physical damage
– Power failure/surge
– Hardware failure
– Software crashing
3
8(b)
Any three from:
– Online shopping // Online payment systems // Online booking
– Email
– Cloud based storage
– Intranet/extranet
– VPN
– VoIP // video conferencing
– Instant messaging (IM) // social networking // online gaming
3
© UCLES 2017
Page 7 of 10
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8(c)
© UCLES 2017
Answer
1 mark for identifying, 1 mark for description
October/November
2017
Marks
6
–
–
Strong password
To make it difficult to hack an account
–
–
Biometric device
To use data that is difficult to fake as a password
–
–
–
–
TLS // Encryption
To make data meaningless if intercepted
To encrypt data that is exchanged (TLS only)
More secure than SSL (TLS only)
–
–
–
Anti-spyware (software)
To find and remove any spyware that is installed on a computer
To help stop key loggers recording key presses
–
–
–
Firewall
To help prevent unauthorised access to an account
Blocks any requests that do not meet/match the criteria
–
–
Authentication (card reader at home)/mobile security code app/two-step verification
To add another level of identification of the user
–
–
Use of drop-down boxes (or equivalent)
So key loggers cannot record the key presses
–
–
Proxy server
To divert an attack away from the main system
Page 8 of 10
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November
2017
Marks
9(a)
Any four from:
– (Red) laser is used
– (Laser beams) shines onto surface of the disk
– It is rotated (at a constant speed) to be read
– Surface is covered in a track (that spirals from the centre)
– Data is represented on the surface using pits and lands
– Pits and lands represent binary values
– Pits reflect light back differently (to the area in between/land)
– Optical device can determine the binary value from the light reflection
4
9(b)
1 mark for calculation, 1 mark for correct answer:
2
9(c)
© UCLES 2017
–
–
1000 × 16
16000/8
–
Answer is 2000 bytes
Four from: (Max 2 for either primary or secondary)
4
–
–
Primary RAM and ROM
Secondary HDD and SSD
–
–
Primary is directly accessible by CPU
Secondary is not directly accessible by CPU
–
–
Primary is internal to computer
Secondary can be internal or external to the computer
–
–
Primary stores boot up instructions and can hold data whilst being processed
Secondary stores files/software
–
–
Primary has faster access speed
Secondary has a slower access speed
–
–
Primary has both volatile and non-volatile
Secondary is non-volatile
Page 9 of 10
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
10
October/November
2017
Answer
Marks
1 mark for each correct tick
6
true
(9)
Statement
9
Assembly language uses mnemonic codes.
9
Assembly language programs do not need a translator to be executed.
Assembly language is a low-level programming language.
9
Assembly language is specific to the computer hardware.
9
9
Assembly language is machine code.
Assembly language is often used to create drivers for hardware.
© UCLES 2017
false
(9)
Page 10 of 10
9
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 0 0 4 9 7 9 6 5 7 1 *
0478/12
COMPUTER SCIENCE
October/November 2017
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
DC (NH/SW) 138025/2
© UCLES 2017
[Turn over
2
1
A robot arm in a factory is programmed to move products.
The binary instructions to operate the robot arm are:
Operation
Binary Instruction
UP
1
1
1
1
DOWN
0
0
0
1
LEFT
1
0
0
1
RIGHT
0
1
1
0
OPEN
1
1
0
0
CLOSE
0
0
1
1
The instructions are entered as hexadecimal values.
An operator enters the values:
9
1
C
3
F
Convert the values and write down the operation (e.g. RIGHT) carried out by the robot arm.
9
.............................................................................
1
.............................................................................
C
.............................................................................
3
.............................................................................
F
.............................................................................
© UCLES 2017
0478/12/O/N/17
[5]
3
2
Storage devices and storage media can be categorised as primary, secondary or off-line.
Write primary, secondary or off-line next to each storage device or medium to indicate its most
suitable category.
3
HDD
....................................................................................................................................
RAM
....................................................................................................................................
ROM
....................................................................................................................................
CD-ROM
....................................................................................................................................
SSD
....................................................................................................................................
DVD-RAM
....................................................................................................................................
[6]
(a) Explain the differences between the binary number system and the denary number system.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
(b) Explain the process of converting the binary number 1010 into a denary number.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[5]
© UCLES 2017
0478/12/O/N/17
[Turn over
4
4
A file server is used as a central data store for a network of computers.
Rory sends data from his computer to a file server that is approximately 100 metres away.
It is important that the data is transmitted accurately. Rory needs to be able to read data from and
write data to the file server at the same time.
(a) (i)
Use ticks (3) to identify the most suitable data transmission methods for this application.
Method 1
Tick
(3)
Method 2
Serial
Simplex
Parallel
Half-duplex
Tick
(3)
Duplex
[2]
(ii)
Explain why your answer to part (a)(i) is the most suitable data transmission.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[4]
© UCLES 2017
0478/12/O/N/17
5
(b) Identify and describe two methods of error checking that can be used to make sure that the
data stored after transmission is accurate.
Method 1 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Method 2 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2017
0478/12/O/N/17
[Turn over
6
5
Raj is using the Internet to do some online shopping. He visits a website that tells him that it uses
cookies.
(a) Explain what is meant by the term cookies.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
(b) Give two examples of the use of cookies.
Example 1 .................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Example 2 .................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
© UCLES 2017
0478/12/O/N/17
7
6
Selma writes the following four answers in her Computer Science examination.
State which computer terms she is describing.
“It is a signal. When the signal is received it tells the operating system that an event has occurred.”
Selma is describing ..........................................................................................................................
“It takes source code written in a high level language and translates it into machine code. It
translates the whole of the source code at once.”
Selma is describing ..........................................................................................................................
“The part of the central processing unit (CPU) that carries out calculations.”
Selma is describing ..........................................................................................................................
“When data is transmitted, if an error is detected in the data received a signal is sent to ask for the
data to be retransmitted. This continues until the data received is correct.”
Selma is describing ..........................................................................................................................
[4]
© UCLES 2017
0478/12/O/N/17
[Turn over
8
7
Draw a logic circuit to represent the logic statement:
X = 1 if (A is NOT 1 AND B is 1) AND (A is NOT 1 AND C is NOT 1) OR (B is 1 AND C is 1)
A
X
B
C
[7]
© UCLES 2017
0478/12/O/N/17
9
8
(a) A computer has 2048 MB of RAM.
How many GB of RAM does the computer have?
Show your working.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
..............................GB
[2]
(b) Describe one item that is stored in RAM.
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(c) Explain three ways that RAM is different to ROM.
1 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
3 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2017
0478/12/O/N/17
[Turn over
10
9
Anna has a farm that grows fruit.
She has a system that monitors the conditions for growing the fruit.
Sensors are used in this system.
(a) Explain what is meant by the term sensor.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(b) State two sensors that could be used in this system and describe how they could be used.
Sensor 1 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Sensor 2 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2017
0478/12/O/N/17
11
10 (a) Describe what is meant by Transport Layer Security (TLS).
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
(b) Name three different applications of TLS.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
© UCLES 2017
0478/12/O/N/17
[Turn over
12
11
Complete the paragraphs choosing the correct five terms from the list. Each term can only be
used once:
•
Ethics
•
Freeware
•
Free Software
•
Hacking
•
Malware
•
Plagiarism
•
Shareware
•
Virus
Taking another person’s work from the Internet and claiming it as your own is called
............................................. . It is possible to protect your work online with copyright.
One product that people may want to protect is software. ............................................. does allow
a person to share, copy and change software freely, but ............................................. does not
allow a person to do this legally. Software that has a licence allowing free use for a trial period
is called ............................................ . The name given to this area of Computer Science is
............................................. .
[5]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017
0478/12/O/N/17
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
Paper 1
October/November 2017
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2017 series for most
Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level
components.
® IGCSE is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 9 printed pages.
© UCLES 2017
[Turn over
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
1 mark per correct instruction:
October/November
2017
Marks
5
9 – LEFT
1 – DOWN
C – OPEN
3 – CLOSE
F – UP
Question
2
Answer
1 mark for each correct category:
Marks
6
HDD – Secondary
RAM – Primary
ROM – Primary
CD-ROM – Off-line
SSD – Secondary
DVD-RAM – Off-line
Question
3(a)
© UCLES 2017
Answer
Any four from (Max 2 per number system) :
Marks
4
•
•
A binary number system is a base-2 system
A denary number system is a base-10 system
•
•
A binary number system uses 0 and 1 values
A denary number system uses 0 to 9 values
•
•
A binary number system has units/ placeholders/column headings that increase by the power of 2
A denary number system has units/ placeholders/column headings that increase by the power of 10
•
Binary has more digit for the same value// Denary has less digits for the same value
Page 2 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(b)
Answer
Five from:
• Correct column headings / place holders by example
• Correctly place a 1 or a 0 for each column
• Identify the columns to be added
• Add together the (denary) values identified «
• « this will give a total which is the denary number/answer
• Answer is 10
Question
Answer
4(a)(i)
Method 1
Serial
Parallel
Tick (9)
9
Method 2
© UCLES 2017
5
Marks
2
Tick (9)
Half-duplex
9
Any four from (Max 3 for serial):
• Serial has less/lower interference
• Serial is (more) reliable/accurate over distances
• In serial the bits won’t be skewed
• In serial it is easier to collate the bits together again after transmission
•
•
Marks
Simplex
Duplex
4(a)(ii)
October/November
2017
Duplex transmits data in both directions at the same time
simplex/half-duplex/remaining methods won’t allow read and write at same time
Page 3 of 9
4
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(b)
October/November
2017
Answer
1 mark for error checking method, 2 marks for description:
Checksum
• A value is calculated from the data // Description of calculation
• Value is transmitted with data
• Value is recalculated after transmission
• If the values match the data is (more likely to be) accurate
Parity check
• A parity bit is transmitted with each byte of data
• Odd or even (parity can be used)
• Counts / checks number of 1’s // counts / checks to see if 1’s are even // counts / checks to see if 1’s are odd
• (Each byte is) checked after transmission to see if it matches the odd/even parity used
Automatic Repeat Request (ARQ)
• Uses acknowledgement and timeout
• When a device detects an error in data transmission it asks for the packet to be resent / no error detected, positive
acknowledgment sent
• The sending device resends the packet after the request to resend/ timeout received
• This process is continuous until the packet received is correct/until the ARQ limit is reached
Echo (check)
• Copy of data is sent back to sender
• Data is compared to see if it matches
• If it does not match error detected
© UCLES 2017
Page 4 of 9
Marks
6
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November
2017
Marks
5(a)
Any four from:
• Data / files
• Stored in a text file
• Downloaded to a user’s computer when a website is visited // webserver sends to web browser
• Stored on a user’s computer
• Stored by a browser
• Detected by the website when it is visited again
4
5(b)
Any two from: e.g.
• To store personal information/data
• To store login details
• To save items in an online shopping basket
• To track/save internet surfing habits // to track website traffic
• To carry out targeted advertising
• To store payment details
• To customise a webpage // to store user preferences
• Store progress in online games/quizzes
2
Question
6
© UCLES 2017
Answer
1 mark for each correct term, in this order:
• Interrupt
• Compiler
• ALU/Arithmetic and Logic Unit
• ARQ/Automatic repeat request
Marks
4
Page 5 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7
© UCLES 2017
Answer
1 mark for each correct logic gate with the correct input(s)
Page 6 of 9
October/November
2017
Marks
7
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8(a)
8(b)
8(c)
© UCLES 2017
October/November
2017
Answer
1 mark for correct calculation method, 1 mark for correct answer:
•
•
2048/1024 (or 1024 × 2)
2 GB
•
•
Instructions/programs/data
« currently in use
Marks
2
2
Any three from:
• RAM is volatile, ROM is non-volatile
• RAM is temporary, ROM is (semi) permanent
• RAM normally has a larger capacity than ROM
• RAM can be edited ROM cannot be edited // Data can be read from and written to RAM, ROM can only be read from.
Page 7 of 9
3
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
9(a)
9(b)
Answer
•
•
It is an input device
It measures/takes (physical) readings of the surrounding environment / environment by example / physical properties
1 mark for each sensor, 2 marks for each description:
Marks
2
6
Moisture (sensor)
• To measure the water content of the soil
• To alert when the soil is too dry or too wet/needs watering
pH (sensor)
• To measure how acidic/alkaline the soil is
• To alert when there may be something polluting the soil
Light (sensor)
• To measure the brightness of the environment
• To alert when the fruit has too little/too much light
Temperature (sensor)
• To measure the temperature of the environment
• To alert when it is too hot/too cold for the fruit to grow
Gas (sensor)
• To measure the amount of CO2/oxygen present
• To alert when too much CO2/oxygen present
Humidity (sensor)
• To measure the water content in the air
• To alert when the air is too dry
Infra-red / motion (sensor)
• To measure level of infra-red/microwaves deflected
• To alert to any intruders e.g. animals stealing the fruit
© UCLES 2017
October/November
2017
Page 8 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November
2017
Marks
10(a)
Any three from:
• It is a (security) protocol
• It encrypts data (sent over the web/network)
• It is the updated version of SSL
• It has two layers
• It has a handshake layer
• It has a record layer
3
10(b)
1 mark for each correct application, examples could include:
• Online banking
• Online shopping // Online payment systems
• Email
• Cloud based storage
• Intranet/extranet
• VPN
• VoIP
• Instant messaging (IM) // social networking
3
Question
11
Answer
1 mark for each correct missing word, in the correct order:
•
•
•
•
•
© UCLES 2017
Plagiarism
Free software
Freeware
Shareware
Ethics
Page 9 of 9
Marks
5
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 3 0 0 2 9 8 4 7 2 8 *
0478/13
COMPUTER SCIENCE
October/November 2017
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
The syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (CE/SW) 152857
© UCLES 2017
[Turn over
2
1
A washing machine has a small display screen built into it.
One use of the display screen is to show an error code when a problem has occurred with a
washing cycle.
(a) State whether the display screen is an input, output or storage device.
...............................................................................................................................................[1]
(b) The display screen shows a hexadecimal error code:
E04
This error code means that the water will not empty out of the washing machine.
Convert this error code to binary.
[3]
(c) State why hexadecimal is used to display the error code.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[1]
(d) Identify three sensors that could be used in the washing machine.
State what each sensor could be used for.
Sensor 1 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
Sensor 2 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
Sensor 3 ...................................................................................................................................
Use ...........................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2017
0478/13/O/N/17
3
2
Data files are stored in different file formats.
Complete the table by providing a suitable file format for each file type. The first one has been
done for you.
File type
Pictures
File format
.JPEG
Text
Sound
Video
[3]
3
(a) An example of a Uniform Resource Locator (URL) is:
http://www.cie.org.uk/index.htm
Part 1
Part 2
Part 3
Identify the three parts that make up this URL.
Part 1 ........................................................................................................................................
Part 2 ........................................................................................................................................
Part 3 ........................................................................................................................................
[3]
(b) Describe what is meant by an Internet Protocol (IP) address.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
© UCLES 2017
0478/13/O/N/17
[Turn over
4
4
Six components of a computer system and six descriptions are shown.
Draw a line to match each component with the most suitable description.
Component
Description
Arithmetic Logic
Unit (ALU)
Used to connect together
the internal components
of the CPU.
Buses
Used to carry out
calculations on data.
Control Unit
(CU)
Used to temporarily hold
data and instructions
during processing.
Immediate Access
Store (IAS)
Used to allow interaction
with the computer.
Input/Output
Used to hold data and
instructions before they
are processed.
Registers
Used to manage the flow
of data through the CPU.
[5]
© UCLES 2017
0478/13/O/N/17
5
5
(a) Draw a logic circuit for the logic statement:
X = 1 if ((A is 1 AND B is 1) OR (A is NOT 1 AND C is 1))
A
X
B
C
[4]
© UCLES 2017
0478/13/O/N/17
[Turn over
6
(b) Draw the symbol for an XOR gate and explain the function of this logic gate.
Explanation ...............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[5]
6
Describe the operation of a 2D scanner and a 3D scanner.
2D .....................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
3D .....................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2017
0478/13/O/N/17
7
7
Six statements about firewalls are shown.
Tick (3) to show whether each statement is true or false.
Statement
true
(3)
false
(3)
Firewalls can monitor incoming and
outgoing traffic.
Firewalls operate by checking traffic against
a set of rules.
Firewalls cannot block access to a certain
website.
Firewalls can be software and hardware.
Firewalls can act as intermediary servers.
Firewalls can block unauthorised traffic.
[6]
© UCLES 2017
0478/13/O/N/17
[Turn over
8
8
(a) Data is valuable. It needs to be kept secure and it can easily be damaged.
Give three different ways that data can be accidentally damaged.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
3 ................................................................................................................................................
...................................................................................................................................................
[3]
(b) The Secure Socket Layer (SSL) protocol can be used to securely transmit data in online
banking.
State three other different applications that use SSL.
Application 1 .............................................................................................................................
Application 2 .............................................................................................................................
Application 3 .............................................................................................................................
[3]
© UCLES 2017
0478/13/O/N/17
9
(c) Online banking is increasing in popularity.
Online banking can be a risk as it can raise a number of security issues. SSL can be used as
a security method to make online banking safer.
Identify and describe three other security methods that could be used to make online banking
safer.
Security method 1 .....................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Security method 2 .....................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Security method 3 .....................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2017
0478/13/O/N/17
[Turn over
10
9
(a) Optical storage media can be used to store data.
Describe how the data is read from a Compact Disc (CD).
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
(b) Kamil wants to store a 16-bit colour image file. The image size is 1000 pixels.
Calculate the size of the file.
Give your answer in bytes. Show your working.
Working .....................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Answer ............................... bytes
[2]
(c) Describe the differences between primary and secondary storage.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
© UCLES 2017
0478/13/O/N/17
11
10 Six statements about assembly language are shown.
Tick (3) whether the statement is true or false.
Statement
true
(3)
false
(3)
Assembly language uses mnemonic codes.
Assembly language programs do not need
a translator to be executed.
Assembly language is a low-level
programming language.
Assembly language is specific to the
computer hardware.
Assembly language is machine code.
Assembly language is often used to create
drivers for hardware.
[6]
© UCLES 2017
0478/13/O/N/17
12
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017
0478/13/O/N/17
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
Paper 1
October/November 2017
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2017 series for most
Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level
components.
® IGCSE is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 10 printed pages.
© UCLES 2017
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November
2017
Marks
1(a)
Output
1
1(b)
1 mark for each correct conversion
3
E
1
1
0
1
0
0
0
4
0
0
0
1
0
0
1(c)
Any one from:
– Hexadecimal codes can fit in a smaller display rather than a full text based message
– Smaller amount of memory needed to store the hex error messages than text based
1
1(d)
1 mark for correct sensor, 1 mark for corresponding use
Possible examples could include:
6
© UCLES 2017
–
–
Temperature (sensor)
To monitor the temperature of the water
–
–
Pressure (sensor)
To monitor the level of water in the washing machine
–
–
Motion (sensor)
To monitor whether the drum is still in motion
–
–
pH (sensor)
To monitor the level of water hardness/detergent present in the water
Page 2 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2
Answer
1 mark for each correct file format e.g.
3(a)
3(b)
© UCLES 2017
File format
Pictures
.JPEG
Text
.doc, .txt, .rtf,
.docx, .odt .pdf
Sound
.mp3, .wav, .aif,
.flac, .mid
Video
.mp4, .flv, .wmv
Answer
–
–
–
Part 1
Part 2
Part 3
Marks
3
File type
Question
October/November
2017
(access) protocol
domain (name)
filename
Marks
3
Four from:
– IP address is used to identify a device (on the Internet / network)
– IP address is allocated by the network/ ISP
– Can be used in place of URL
– IP addresses can be IPv4 or IPv6
– IP address can be static «
– ... meaning it doesn’t change each time it is connected to the Internet
– IP address can be dynamic «.
– « meaning that it can change each time a device is connected to the Internet
– Any valid example (e.g. xxx.xxx.xxx.xxx or xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx)
Page 3 of 10
4
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4
© UCLES 2017
Answer
1 mark for each correct line up to a total of 5 marks
October/November
2017
Marks
5
Page 4 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(a)
© UCLES 2017
Answer
1 mark for each correct logic gate
October/November
2017
Marks
4
Page 5 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(b)
Answer
1 mark for correct logic gate symbol:
October/November
2017
Marks
5
Any four from:
– similar to an OR gate
– It has (at least) two inputs
– Output will be high/1 if both inputs are different
– Output will be high/1 if either input is high
– Output will be low/0 if both inputs are high
– Output will be low/0 if both inputs are low
Question
6
© UCLES 2017
Answer
Any six from:
Marks
6
–
–
–
–
–
2D
(Scanner) shines a light onto the surface of a document // Light moves across document
Reflected light is captured
Uses mirrors and lenses
Captured image is converted into a digital file
Produces a 2D digital image
–
–
–
–
3D
Scanners shines a laser (or light) over the surface of a 3D object
Records measurements of the geometry/dimensions of the object
Measurements are converted to digital file
Produces a 3D digital model
Page 6 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7
October/November
2017
Answer
Marks
1 mark for each correct tick
6
true
(9)
Statement
Firewalls can monitor incoming and outgoing traffic.
9
Firewalls operate by checking traffic against a set of rules.
9
9
Firewalls cannot block access to a certain website.
9
Firewalls can be software and hardware.
9
Firewalls can act as intermediary servers.
9
Firewalls can block unauthorised traffic.
Question
false
(9)
Answer
Marks
8(a)
Any three from:
– Human error (e.g. deleting/overwriting data)
– Physical damage
– Power failure/surge
– Hardware failure
– Software crashing
3
8(b)
Any three from:
– Online shopping // Online payment systems // Online booking
– Email
– Cloud based storage
– Intranet/extranet
– VPN
– VoIP // video conferencing
– Instant messaging (IM) // social networking // online gaming
3
© UCLES 2017
Page 7 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8(c)
© UCLES 2017
Answer
1 mark for identifying, 1 mark for description
October/November
2017
Marks
6
–
–
Strong password
To make it difficult to hack an account
–
–
Biometric device
To use data that is difficult to fake as a password
–
–
–
–
TLS // Encryption
To make data meaningless if intercepted
To encrypt data that is exchanged (TLS only)
More secure than SSL (TLS only)
–
–
–
Anti-spyware (software)
To find and remove any spyware that is installed on a computer
To help stop key loggers recording key presses
–
–
–
Firewall
To help prevent unauthorised access to an account
Blocks any requests that do not meet/match the criteria
–
–
Authentication (card reader at home)/mobile security code app/two-step verification
To add another level of identification of the user
–
–
Use of drop-down boxes (or equivalent)
So key loggers cannot record the key presses
–
–
Proxy server
To divert an attack away from the main system
Page 8 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November
2017
Marks
9(a)
Any four from:
– (Red) laser is used
– (Laser beams) shines onto surface of the disk
– It is rotated (at a constant speed) to be read
– Surface is covered in a track (that spirals from the centre)
– Data is represented on the surface using pits and lands
– Pits and lands represent binary values
– Pits reflect light back differently (to the area in between/land)
– Optical device can determine the binary value from the light reflection
4
9(b)
1 mark for calculation, 1 mark for correct answer:
2
9(c)
© UCLES 2017
–
–
1000 × 16
16000/8
–
Answer is 2000 bytes
Four from: (Max 2 for either primary or secondary)
4
–
–
Primary RAM and ROM
Secondary HDD and SSD
–
–
Primary is directly accessible by CPU
Secondary is not directly accessible by CPU
–
–
Primary is internal to computer
Secondary can be internal or external to the computer
–
–
Primary stores boot up instructions and can hold data whilst being processed
Secondary stores files/software
–
–
Primary has faster access speed
Secondary has a slower access speed
–
–
Primary has both volatile and non-volatile
Secondary is non-volatile
Page 9 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
10
October/November
2017
Answer
Marks
1 mark for each correct tick
6
true
(9)
Statement
9
Assembly language uses mnemonic codes.
9
Assembly language programs do not need a translator to be executed.
Assembly language is a low-level programming language.
9
Assembly language is specific to the computer hardware.
9
9
Assembly language is machine code.
Assembly language is often used to create drivers for hardware.
© UCLES 2017
false
(9)
Page 10 of 10
9
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 2 7 7 2 1 0 6 8 2 5 *
0478/11
COMPUTER SCIENCE
May/June 2018
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (SR/SW) 163639/3 R
© UCLES 2018
[Turn over
2
1
Jane answers an examination question about computers and data correctly.
Six different words or numbers have been removed from her answer.
Complete the sentences in Jane’s answer, using the list given. Not all items in the list need to be
used.
•
•
•
•
•
•
•
•
2
10
16
analogue
binary
denary
digital
hexadecimal
As humans, we process …………………………………… data, but a computer cannot
process this type of data. For a computer to be able to process data it needs to be
converted to …………………………………… data.
As humans, we mostly use a …………………………………… number system;
this is a base …………………………………… number system.
Computers use a …………………………………… number system;
this is a base …………………………………… number system.
2
[6]
Dheeraj identifies three hexadecimal numbers.
Write the denary number for each of the three hexadecimal numbers:
2A ....................................................................................................
101 ...................................................................................................
21E ..................................................................................................
[3]
Working Space
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
© UCLES 2018
0478/11/M/J/18
3
3
The three binary numbers in the registers A, B and C have been transmitted from one computer to
another.
Parity bit
Register A
1
0
0
1
1
0
0
0
Register B
0
1
1
0
0
1
1
1
Register C
1
0
0
1
1
0
0
1
One binary number has been transmitted incorrectly. This is identified through the use of a parity bit.
Identify which register contains the binary number that has been transmitted incorrectly. Explain
the reason for your choice.
The binary number that has been transmitted incorrectly is in Register ..........................................
Explanation ......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
© UCLES 2018
0478/11/M/J/18
[Turn over
4
4
Michele wants to email a file to Elsa. The file is too large so it must be compressed.
(a) Name two types of compression that Michele could use.
Compression type 1 ..................................................................................................................
Compression type 2 ..................................................................................................................
[2]
(b) The file Michele is sending contains the source code for a large computer program.
Identify which type of compression would be most suitable for Michele to use.
Explain your choice.
Compression type ......................................................................................................................
Explanation ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2018
0478/11/M/J/18
5
5
Six components of the Von Neumann model for a computer system and six descriptions are given.
Draw a line to match each component to the most suitable description.
Component
Description
Immediate
access store
(IAS)
Holds data and instructions when they are
loaded from main memory and are waiting
to be processed.
Register
Holds data temporarily that is currently
being used in a calculation.
Control unit
(CU)
Holds data or instructions temporarily
when they are being processed.
Accumulator
(ACC)
Manages the flow of data and interaction
between the components of the processor.
Arithmetic logic
unit (ALU)
Carries out the calculations on data.
Bus
Pathway for transmitting data and
instructions.
[5]
© UCLES 2018
0478/11/M/J/18
[Turn over
6
6
Consider the logic statement:
X = 1 if ((A is NOT 1 OR B is 1) NOR C is 1) NAND ((A is 1 AND C is 1) NOR B is 1)
(a) Draw a logic circuit to represent the given logic statement.
A
B
X
C
[6]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2018
0478/11/M/J/18
7
7
Translators, such as a compiler and an interpreter, are used when writing and running computer
programs.
Describe how a compiler and an interpreter translates a computer program.
Compiler ...........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Interpreter .........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2018
0478/11/M/J/18
[Turn over
8
8
A supermarket uses a barcode scanner to read the barcodes on its products.
(a) Describe how the barcode scanner reads the barcode.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
(b) Explain how the barcode system could help the supermarket manage its stock.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
(c) An infrared touch screen is used to view and navigate the supermarket stock system.
Explain how the infrared touch screen detects a user’s touch.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2018
0478/11/M/J/18
9
(d) The supermarket uses secondary storage and off-line storage to store data about its stock.
Explain what is meant by secondary storage and off-line storage.
Secondary storage ...................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Off-line storage .........................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
9
A business wants to use a biometric security system to control entry to the office.
The system will use a biometric device and a microprocessor.
Explain how the biometric security system will make use of the biometric device and the
microprocessor to control entry to the office.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2018
0478/11/M/J/18
[Turn over
10
10 RockICT is a music business that has a website to allow customers to view and buy the products
it sells.
The website consists of web pages.
(a) Describe what is meant by HTML structure and presentation for a web page.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
(b) The URL for the music company’s website is:
https://www.rockict.net/index.htm
Part 1
(i)
Part 2
Identify what Part 1 and Part 2 represent in this URL.
Part 1 ................................................................................................................................
Part 2 ................................................................................................................................
[2]
(ii)
Describe what is meant by https.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
© UCLES 2018
0478/11/M/J/18
11
(c) When a customer enters the website, a message is displayed:
“RockICT makes use of cookies. By continuing to browse you are agreeing to our use of
cookies.”
Explain why the music company uses cookies.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(d) The music company is concerned about the security of its website.
The company uses a proxy server as part of its security system.
Describe the role of a proxy server in the security system.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2018
0478/11/M/J/18
12
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2018
0478/11/M/J/18
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
Paper 1
May/June 2018
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2018 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and
some Cambridge O Level components.
IGCSE™ is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
© UCLES 2018
[Turn over
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2018
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2018
Page 2 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2018
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2018
Page 3 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
1 mark for each correct answer, in the given order:
−
−
−
−
−
−
1 mark for each correct conversion:
3
Answer
1 mark for correct register, 3 marks for reason:
−
Marks
4
Register C
Any three from:
− Count the number of 1/0 bits (in each byte/register)
− Two bytes/registers have an odd number of 1/0 bits // Two use odd parity
− Odd parity must be the parity used
− One byte/register has an even number of 1/0 bits // One uses even parity
− One with an even number of one bits/even parity is incorrect // Register C should have odd parity
© UCLES 2018
Marks
42
257
542
Question
3
6
Answer
−
−
−
Marks
analogue
digital
denary
10
binary
2
Question
2
May/June 2018
Page 4 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)
May/June 2018
Answer
1 mark for each correct answer:
Marks
2
Lossy (compression)
Lossless (compression)
4(b)
1 mark for correct compression, 3 marks for description:
−
Lossless (compression)
Any three from:
− The file can be restored/decompressed to the exact same state it was before compression/ to original
− (It is a computer program so) no data can be lost // Lossy would remove data
− Will not run correctly (with any other compression)
− (Lossless) will give repeating words/sections of word a value// RLE is used // Other valid examples of methods of
lossless compression
− Value is recorded in an index
© UCLES 2018
Page 5 of 12
4
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5
Answer
1 mark for each correct line, up to a maximum of 5 marks:
Component
Immediate access
store (IAS)
© UCLES 2018
Description
Holds data and instructions when they are
loaded from main memory and are waiting
to be processed.
Register
Holds data temporarily that is currently
being used in a calculation.
Control unit
(CU)
Holds data or instructions temporarily when
they are being processed.
Accumulator
(ACC)
Manages the flow of data and interaction
between the components of the processor.
Arithmetic logic
unit (ALU)
Carries out the calculations on data.
Bus
Pathway for transmitting data and
instructions.
Page 6 of 12
May/June 2018
Marks
5
0478/11
Question
6(a)
© UCLES 2018
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
1 mark for each correct logic gate (with the correct direction of input(s))
Page 7 of 12
May/June 2018
Marks
6
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(b)
© UCLES 2018
Answer
May/June 2018
Marks
4 marks for 8 correct outputs
3 marks for 6 or 7 correct outputs
2 marks for 4 or 5 correct outputs
1 mark for 2 or 3 correct outputs
4
A
B
C
Working space
X
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
1
Page 8 of 12
0478/11
Question
7
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Compiler
Any three from:
− Translates high-level language into machine code/low level language
− Translates (the source code) all in one go/all at once
− Produces an executable file
− Produces an error report
May/June 2018
Marks
6
Interpreter
Any three from:
– Translates high-level language into machine code/low level language
− Translates (the source code) line by line/statement by statement
– Stops if it finds an error
– Will only continue when error is fixed
Question
Answer
Marks
8(a)
Any four from:
− Shines light / (red) laser at barcode
− Light is called an illuminator
− Light is reflected back // White lines reflect light // Black lines reflect less light/absorbs light
− Sensors / photoelectric cells detect the light
− Different reflections / bars will give different binary values / digital values // pattern converted to digital values
− A microprocessor interprets the data
4
8(b)
Any three from:
− barcode identifies a (unique) product
− barcode can be used to look up product (in a database)
− data about stock levels can be stored on a system
− stock can be automatically deducted from the system
− can check stock is below a certain level // check stock level
− automatic re-order // Alerts when stock is low
− automatically update new stock level
− to locate if an item of stock is available in another location
3
© UCLES 2018
Page 9 of 12
0478/11
Question
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2018
Answer
Marks
8(c)
Any four from:
− (Infrared) rays are sent across screen (from the edges)
− Has sensors around edge // Sensors capture beams
− (Infrared) rays form a grid across the screen
− (Infrared) ray is broken (by a finger blocking a beam)
− Calculation is made (on where beam is broken) to locate the ‘touch’ // Co-ordinates are used to locate the touch
4
8(d)
Secondary Storage – any two from:
− Not directly accessed by the CPU
− Non-volatile storage
− Secondary is internal to the computer/device
− An example of secondary storage would be HDD/SSD
4
Off-line storage – any two from:
− Non-volatile storage
− Off-line storage is storage that is removable from a computer/device // not internal // portable
− An example of off-line storage would be CD/DVD/USB stick/SD card/magnetic tape/ external HDD/SSD
Question
9
© UCLES 2018
Answer
Any six from:
− Suitable biometric device, such as fingerprint scanner/retina/eye/iris scanner/face recognition/voice
recognition/palm scanner // description of use e.g. use fingerprint on device
− Sensor (in biometric device) captures/takes data/readings (of user)
− Data/readings are converted from analogue to digital (using ADC)
− Data/reading sent to the microprocessor
− Data/readings compared to stored values/data «
− « if data/readings match user can enter
− « if data/readings do not match user is declined entry // user asked to try again «
− « alert may be sent to security // alarm may sound
Page 10 of 12
Marks
6
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
10(a)
10(b)(i)
Answer
10(c)
© UCLES 2018
Marks
Any four from:
− Structure and presentation are defined using (mark-up) tags
− Structure and presentation dictate the appearance of the website
− Structure is used for layout
− Example of structure
− Presentation is used for formatting / style
− Example of formatting
− Separate file / CSS can be used for presentation content
4
1 mark for each correct part
2
−
−
10(b)(ii)
May/June 2018
domain (name)
file name/webpage name
Any two from:
− Hypertext Transfer Protocol Secure // it is the access protocol // It is a protocol
− It means the website uses SSL/TLS
− It means data sent (to and from the webserver) is encrypted
2
Any two from e.g. :
− To store items that a customer has added to an online shopping basket
− To store a customer’s credit card details
− To store log-in details
− To track what product a customer browses // Track music preferences
− Targeted advertising // making recommendations
− Personalises/customises the experience
− Shows who are new and returning customers
− To speed up log-in times
− To speed up/allow single click purchases
− Improves the experience
2
Page 11 of 12
0478/11
Question
10(d)
© UCLES 2018
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Any four from:
− Prevents direct access to the webserver // Sits between user and webserver
− If an attack is launched it hits the proxy server instead // can be used to help prevent DDOS // help prevent
hacking of webserver
− Used to direct invalid traffic away from the webserver
− Traffic is examined by the proxy server // Filters traffic
− If traffic is valid the data from the webserver will be obtained by the user
− If traffic is invalid the request to obtain data is declined
− Can block requests from certain IP addresses
Page 12 of 12
May/June 2018
Marks
4
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 8 0 0 3 2 9 5 9 2 1 *
0478/12
COMPUTER SCIENCE
May/June 2018
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (SC/SW) 150229/2
© UCLES 2018
[Turn over
2
1
Different units of data can be used to represent the size of a file, as it changes in size.
Fill in the missing units of data, using the list given:
•
byte
•
gigabyte (GB)
•
megabyte (MB)
•
nibble
The units of data increase in size from smallest to largest.
Smallest
bit
………………………………………………..
………………………………………………..
kilobyte (kB)
………………………………………………..
………………………………………………..
Largest
terabyte (TB)
[4]
2
(a) Nancy has captured images of her holiday with her camera. The captured images are stored
as digital photo files on her camera.
Explain how the captured images are converted to digital photo files.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2018
0478/12/M/J/18
3
(b) Nancy wants to email the photos to Nadia.
Many of the photos are very large files, so Nancy needs to reduce their file size as much as
possible.
Identify which type of compression would be most suitable for Nancy to use. Explain your
choice.
Compression type .....................................................................................................................
Explanation ...............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
3
A stopwatch uses six digits to display hours, minutes and seconds.
The stopwatch is stopped at:
0 2
Hours
3 1
Minutes
5 8
Seconds
An 8-bit register is used to store each pair of digits.
(a) Write the 8-bit binary numbers that are currently stored for the Hours, Minutes and Seconds.
Hours
Minutes
Seconds
[3]
© UCLES 2018
0478/12/M/J/18
[Turn over
4
(b) The stopwatch is started again and then stopped.
When the watch is stopped, the 8-bit binary registers show:
Hours
0
0
0
0
0
1
0
1
Minutes
0
0
0
1
1
0
1
0
Seconds
0
0
1
1
0
1
1
1
Write the denary values that will now be shown on the stopwatch.
Hours
Minutes
Seconds
[3]
4
Jafar is using the Internet when he gets the message:
“D03, page is not available”
Jafar remembers that hexadecimal is often used to represent binary values in error codes.
Convert the hexadecimal number in the error message into 12-bit binary.
[3]
© UCLES 2018
0478/12/M/J/18
5
5
The three binary numbers in the registers X, Y and Z have been transmitted from one computer to
another.
Parity bit
Register X
1
0
0
1
0
0
1
0
Register Y
1
1
1
0
0
1
1
1
Register Z
1
1
1
0
1
0
0
1
Only one binary number has been transmitted correctly. This is identified through the use of a
parity bit.
Identify which register contains the binary number that has been transmitted correctly. Explain
the reason for your choice.
The binary number that has been transmitted correctly is in Register ............................................
Explanation ......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
© UCLES 2018
0478/12/M/J/18
[Turn over
6
6
Kelvin correctly answers an examination question about the Von Neumann model.
Eight different terms have been removed from his answer.
Complete the sentences in Kelvin’s answer, using the list given.
Not all items in the list need to be used.
•
accumulator (ACC)
•
address bus
•
arithmetic logic unit (ALU)
•
control unit (CU)
•
data bus
•
executed
•
fetches
•
immediate access store (IAS)
•
memory address register (MAR)
•
memory data register (MDR)
•
program counter (PC)
•
saved
•
transmits
The central processing unit (CPU) ....................................................................................
the data and instructions needed and stores them in the
.................................................................................... to wait to be processed.
The .................................................................................... holds the address of the next
instruction. This address is sent to the .................................................................................... .
The data from this address is sent to the .................................................................................... .
The instruction can then be decoded and .................................................................................... .
Any calculations that are carried out on the data are done by the
.................................................................................... . During calculations, the data is temporarily
held in a register called the .................................................................................... .
© UCLES 2018
0478/12/M/J/18
[8]
7
7
Consider the logic statement:
X = 1 if ((A is 1 AND B is NOT 1) NAND C is 1) XOR ((A is 1 AND C is 1) OR B is 1)
(a) Draw a logic circuit to represent the given logic statement.
A
B
X
C
[6]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2018
0478/12/M/J/18
[Turn over
8
8
Dimitri is writing a computer program in a high-level language.
He needs to send just the machine code for the program to his friend, electronically.
It is important that the program is executed as quickly as possible.
Identify which translator will be most suitable for Dimitri to use. Explain your choice.
Type of translator .............................................................................................................................
Explanation ......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
9
An advertisement in a magazine displays this barcode:
(a) Identify this type of barcode.
.............................................................................................................................................. [1]
(b) Explain how the data stored in this barcode is read.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2018
0478/12/M/J/18
9
10 Alexandra has a new mobile device.
It has a touch screen that uses capacitive technology.
(a) Describe how a capacitive touch screen registers Alexandra’s touch.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [4]
(b) Alexandra is wearing gloves because it is cold.
She presses an icon on her touch screen but her action is not registered.
(i)
Explain why the touch screen will not register her touch.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
(ii)
Alexandra does not want to remove her gloves.
Explain how Alexandra could use her mobile device whilst still wearing gloves.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
© UCLES 2018
0478/12/M/J/18
[Turn over
10
11
A factory uses a security system to control a security light. The system uses a sensor and a
microprocessor.
Explain how the security system makes use of the sensor and the microprocessor to control the
security light.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [6]
© UCLES 2018
0478/12/M/J/18
11
12 (a) Selma has some important personal information that she needs to email to her employer.
She wants to make sure that if the personal information is intercepted, it cannot be understood.
(i)
State how Selma could email her personal data more securely.
...................................................................................................................................... [1]
(ii)
Describe how your chosen solution works.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [5]
(b) Selma wants to make sure that the information received is correct.
A parity check can be used to detect errors.
Describe another error detection method that can be used to check the information received
is correct.
Error detection method .............................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2018
0478/12/M/J/18
12
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2018
0478/12/M/J/18
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
Paper 1
May/June 2018
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2018 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and
some Cambridge O Level components.
IGCSE™ is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 10 printed pages.
© UCLES 2018
[Turn over
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2018
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2018
Page 2 of 10
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2018
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2018
Page 3 of 10
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
1 mark for each unit, in the given order:
–
–
nibble
byte
–
–
megabyte (MB)
gigabyte (GB)
May/June 2018
Marks
4
Question
Answer
Marks
2(a)
Any four from:
– Image is converted from analogue to digital (using ADC)
– Image is turned into pixels
– Each pixel is given a binary value
– Pixels form a grid (to create the image)
– Each pixel has a colour
– Pixels are stored in sequence (in a file)
– Meta data is stored (to describe the dimensions/resolution of the image) // It stores the dimensions/colour
depth .etc.
– An example of a suitable photo file format e.g. JPEG
4
2(b)
1 mark for correct compression, 3 marks for explanation:
4
–
Lossy
Any three from:
– Lossy would reduce the file size more (than lossless)
– The redundant data can be removed from the files // by example (must be about redundant data)
– Images can still be a similar quality
– There is no requirement for the files to be exactly the same as original file
– Photos can be sent quicker // faster to upload // faster to download
© UCLES 2018
Page 4 of 10
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(a)
3(b)
Answer
3
Hours
0
0
0
0
0
0
1
0
Minutes
0
0
0
1
1
1
1
1
Seconds
0
0
1
1
1
0
1
0
1 mark for each correct section:
3
5
2
Hours
6
5
Minutes
Question
5
Seconds
Answer
Marks
1 mark for each correct section:
1
1
0
1 mark
© UCLES 2018
Marks
1 mark for each correct register
0
4
May/June 2018
1
3
0
0
0
0
1 mark
0
0
1
1 mark
Page 5 of 10
1
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5
Answer
1 mark for correct register, 3 marks for reason:
–
May/June 2018
Marks
4
Register Y
Any three from:
– Count the number of 1/0 bits (in each byte/register)
– Two bytes/registers have an odd number of 1/0 bits // Two have odd parity
– Even parity must be the parity used
– One byte/register has an even number of 1/0 bits // One uses even parity
– The two with an odd number of one bits/odd parity are incorrect // Register X and Z should have even parity
Question
6
Answer
1 mark for each correct missing word, in the given order:
–
–
–
–
–
–
–
–
© UCLES 2018
fetches
immediate access store // IAS
program counter // PC
memory address register // MAR
memory data register // MDR
executed
arithmetic logic unit // ALU
accumulator // ACC
Page 6 of 10
Marks
8
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
May/June 2018
Marks
7(a)
1 mark for each correct logic gate with correct direct of input(s):
6
7(b)
4 marks for 8 correct outputs
3 marks for 6 or 7 correct outputs
2 marks for 4 or 5 correct outputs
1 mark for 2 or 3 correct outputs
4
© UCLES 2018
A
B
C
Working space
X
0
0
0
1
0
0
1
1
0
1
0
0
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
0
1
1
1
0
Page 7 of 10
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8
Answer
1 mark for correct translator, 3 marks for explanation:
–
May/June 2018
Marks
4
Compiler
Any three from:
– Does not require recompilation // compiled program can be executed without a compiler «
– ... therefore, allows faster execution
– Provides an executable file «
– « therefore, allows him to just send machine code
– Dimitri’s friend does not need translation/compilation software to execute the program
Question
Answer
Marks
9(a)
QR/Quick response
1
9(b)
Any four from:
– Read/scanned using app (on mobile device)
– It is the camera that is used to scan/capture the image
– The three large squares are used to define the alignment // uses alignment targets/modules
– Black squares reflect less light // white squares reflect more light
– The app/device processes the image
– Each small square/pixel is converted to a binary value
4
Question
10(a)
© UCLES 2018
Answer
Any four from:
– Conductive layer
– An electrostatic/electric field is created
– Sensor(s) (around the screen) monitor the electrostatic field
– When touched (electrostatic) charge is transferred to finger
– Location of touch is calculated // Co-ordinates used to calculate touch
Page 8 of 10
Marks
4
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
May/June 2018
Marks
10(b)(i)
Any two from:
– Gloves are not conductive // Gloves are an insulator
– Block current/charge from finger / body / person
– Stop the electrostatic field being disturbed/changed
2
10(b)(ii)
Any two from e.g. (1 mark for method, 1 for expansion):
– She could use a (conductive) stylus«
– « this will allow the charge to be charged/disturbed
2
–
–
She could use capacitive gloves«
« this will allow the charge to be charged/disturbed
–
–
She could use a natural language interface/voice operated interface «
« she could give vocal commands to the device
Question
11
Answer
Any six from:
– Suitable sensor (motion/infra-red)
– Data converted (from analogue) to digital (using ADC)
– Data sent to microprocessor
– Data is compared to stored value/range «
– « if data matches/out of range data security light turned on «
– « waits for suitable period/until no motion detected «
– « light turned off
– Continuous loop/process
Question
12(a)(i)
© UCLES 2018
Answer
Encryption
Marks
6
Marks
1
Page 9 of 10
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
12(a)(ii)
12(b)
Answer
Marks
Any five from:
– Her personal details before encryption is the plain text
– The plain text/her personal details is encrypted using an encryption algorithm
– The plain text/her personal details is encrypted using a key
– The encrypted text is cypher/cipher text
– The key is transmitted separately (from the text)
– The key is used to decrypt the cypher text (after transmission)
5
Any three from a single error method:
– Checksum
– Calculation carried out on data
– (checksum/calculated) value sent with data
– recalculated after transmission and compared to original
– If they do not match an error is present
3
–
–
–
–
–
© UCLES 2018
May/June 2018
ARQ
uses acknowledgment and timeout
A request is sent with data to acknowledge all data is received
Acknowledgement sent back to say all data is received
If no acknowledgement is received in a time frame an error in transmission detected / data automatically resent.
Page 10 of 10
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 0 5 5 7 4 2 2 1 9 3 *
0478/13
COMPUTER SCIENCE
May/June 2018
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (SC/CGW) 148529/3
© UCLES 2018
[Turn over
2
1
State five sensors that could be used in the following applications.
Give a different type of sensor for each application.
Application
Sensor
Weighing a baby in a hospital
Turning off a kettle when the water boils
Controlling an automatic door
Monitoring the air quality in an
aeroplane
Counting cars crossing a bridge
[5]
2
Draw a line to connect each term to the correct application.
Term
Application
Simplex
A telephone that can receive and transmit audio
signals simultaneously.
Duplex
A two-way radio (walkie-talkie) that can receive
and transmit messages, but not at the same time.
Half-duplex
A microphone that transmits data to a MIDI
system.
[2]
© UCLES 2018
0478/13/M/J/18
3
3
Three security issues that could affect users online are phishing, pharming and spam.
Explain what is meant by each security issue.
Phishing ...........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Pharming ..........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Spam ................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2018
0478/13/M/J/18
[Turn over
4
4
A company transmits data to external storage at the end of each day.
(a) Parity checks can be used to check for errors during data transmission.
The system uses odd parity.
(i)
Tick (✓) to show for each of the received bytes whether they have been transmitted
correctly or transmitted incorrectly.
Received byte
Transmitted
correctly
(✓)
Transmitted
incorrectly
(✓)
10001011
10101110
01011101
00100101
[4]
(ii)
State one other method that could be used to check for transmission errors.
...................................................................................................................................... [1]
(b) Data can be transferred using parallel or serial data transmission.
(i)
Describe what is meant by parallel data transmission.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
(ii)
Give one application of parallel data transmission.
...........................................................................................................................................
...................................................................................................................................... [1]
© UCLES 2018
0478/13/M/J/18
5
(iii)
Explain why serial data transmission is normally used for transferring data over a long
distance.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
(c) Data transferred over a network is encrypted to improve data security.
The system uses 64-bit symmetric encryption.
(i)
Explain how encryption improves data security.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
(ii)
Explain one method that could be used to increase the level of security provided by the
encryption.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
© UCLES 2018
0478/13/M/J/18
[Turn over
6
5
(a) Convert the denary number 107 to binary.
.............................................................................................................................................. [1]
(b) Represent the denary number 300 as it would be stored in a 12-bit binary register.
.............................................................................................................................................. [2]
(c) Convert the denary number 179 to hexadecimal.
.............................................................................................................................................. [2]
6
One of the roles of an operating system is to deal with interrupts.
(a) Explain the term interrupt.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [2]
(b) Identify three devices that make use of interrupts.
Device 1 ....................................................................................................................................
Device 2 ....................................................................................................................................
Device 3 ....................................................................................................................................
[3]
© UCLES 2018
0478/13/M/J/18
7
7
A train station uses large touch screens to allow passengers to search for train information and
buy tickets.
(a) State three benefits of using a touch screen in the train station.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
Benefit 3 ...................................................................................................................................
...................................................................................................................................................
[3]
(b) The touch screens at the station use resistive touch technology.
Describe how resistive touch technology works.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2018
0478/13/M/J/18
[Turn over
8
8
A logic circuit is shown below.
A
B
X
C
(a) Complete the truth table for the given logic circuit.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2018
0478/13/M/J/18
9
(b) Draw a logic circuit corresponding to this logic statement:
X = 1 if (A is NOT 1) OR ((B is 1 OR C is 1) AND (B is NOT 1 OR A is NOT 1))
A
B
X
C
[6]
9
Three types of translators are assemblers, compilers and interpreters.
Tick (✓) the appropriate boxes to show which statements apply to each type of translator.
Statement
Assembler
(✓)
Compiler
(✓)
Interpreter
(✓)
Translates highlevel language into
machine code
Provides error
diagnostics
Translates whole
program to object
code in one
operation
Translates and
executes one line
of code at a time
[3]
© UCLES 2018
0478/13/M/J/18
[Turn over
10
10 Explain how an instruction is fetched in a computer based on the Von Neumann model.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [6]
11
Identify three similarities between CDs and DVDs.
1 .......................................................................................................................................................
..........................................................................................................................................................
2 .......................................................................................................................................................
..........................................................................................................................................................
3 .......................................................................................................................................................
..........................................................................................................................................................
[3]
© UCLES 2018
0478/13/M/J/18
11
12 An image is to be stored electronically.
The image is 256 pixels high by 200 pixels wide with a 16-bit colour depth.
Calculate the file size of the image. You must show all of your working.
File size ................................................................................. kB
[3]
13 Describe the role of an Internet Service Provider (ISP).
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [6]
© UCLES 2018
0478/13/M/J/18
12
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2018
0478/13/M/J/18
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
Paper 1
May/June 2018
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2018 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and
some Cambridge O Level components.
IGCSE™ is a registered trademark.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
© UCLES 2018
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2018
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2018
Page 2 of 12
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2018
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2018
Page 3 of 12
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
One mark per each sensor (sensors must be different):
2
Sensor
Weighing a baby in a hospital
Pressure
Turning off a kettle when it boils
Temperature
Controlling an automatic door
Infrared / Light / Pressure
Monitoring the air quality in an aeroplane
Oxygen / Gas / Humidity
Counting cars crossing a bridge
Pressure / Infrared / Magnetic
Answer
Term
Applicaon
Simplex
A telephone that can receive and transmit audio
signals simultaneously.
Duplex
A two-way radio (walkie talkie) that can receive and
transmit messages, but not at the same me.
Half-duplex
A microphone that transmits data to a MIDI system.
Three correct lines = 2 marks
Two or one correct line = 1 mark
© UCLES 2018
Marks
5
Application
Question
May/June 2018
Page 4 of 12
Marks
2
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3
Answer
2 marks per issue from:
May/June 2018
Marks
6
Phishing
– Legitimate looking emails sent to use
– When user clicks on attachment / link sent to fraudulent website
– Asked to reveal/designed to steal sensitive information
Pharming
– Malicious code loaded on user hard drive
– Will redirect URL requests to fraudulent website
– Asked to reveal/designed to steal sensitive information
Spam
–
–
–
–
Junk / unwanted email
Sent to large numbers of people
Used for advertising / spreading malware
Fills up mail boxes
Question
4(a)(i)
Answer
Received Byte
Transmitted
correctly
(9)
© UCLES 2018
4
9
10001011
4(a)(ii)
Transmitted
incorrectly
(9)
Marks
10101110
9
01011101
9
00100101
9
One from:
– ARQ
– Check Sum
1
Page 5 of 12
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(b)(i)
Answer
–
–
Multiple bits / byte(s) sent at the same time
Using multiple wires
May/June 2018
Marks
2
4(b)(ii)
Any one from e.g.:
– Integrated Circuits
– Any appropriate CPU buses
– Any suitable device connection that uses parallel
1
4(b)(iii)
Two from:
– Bits remain synchronised
–
reducing data errors
2
–
–
Only single wire is required
more cost effective to install/manufacture
4(c)(i)
–
–
Encrypted text is meaningless
Need the key to decrypt the text
2
4(c)(ii)
–
–
Increase length / more bits used for key
will generate more possibilities for key / less chance of decryption by brute force method
2
Question
Answer
Marks
5(a)
(0)1101011
1
5(b)
000 100101100
1 mark for three leading zeros, 1 mark for correct binary number
2
5(c)
B3
1 mark for each correct character
2
6(a)
Any two from:
– A signal sent from a device / software
– Requests processor time // Processor stops to service interrupt
– Interrupts have different priorities
2
© UCLES 2018
Page 6 of 12
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(b)
Answer
Any three from e.g.:
– Keyboard
– Printer
– Mouse
Question
7(a)
7(b)
© UCLES 2018
Marks
3
Answer
Any three from:
– Does not require peripherals (mouse or keyboard)
– Number of possible inputs limited / menu driven interface
– Less chance of input error
– Resistant to weather
–
–
–
–
May/June 2018
Uses two/multiple layers
When top layer touched / pushed two layers make contact
Circuit is completed when layers touch
Point of contact is determined/calculated
Page 7 of 12
Marks
3
4
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8(a)
Answer
A
B
C
X
0
0
0
1
0
0
1
1
0
1
0
0
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
1
Marks
4
All 8 for 4 marks
6 or 7 for 3 marks
4 or 5 for 2 marks
2 or 3 for 1 mark
© UCLES 2018
May/June 2018
Page 8 of 12
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
May/June 2018
Answer
Marks
8(b)
6
X
1 mark per gate with correct inputs
© UCLES 2018
Page 9 of 12
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
9
Answer
Statement
Assembler
(9)
Translates highlevel language into
machine code
Compiler
(9)
Interpreter
(9)
9
9
9
Provides error
diagnostics
9
9
Translates whole
program to object
code in one
operation
9
9
Translates and
executes one line
of code at a time
May/June 2018
Marks
3
9
1 mark for each correct column
Question
10
© UCLES 2018
Answer
Any six from:
– Program counter (PC) holds address / location of the instruction
– The address held in PC is sent to MAR
– Address is sent using address bus
– PC is incremented
– The instruction is sent from address in memory to MDR
– Instruction is transferred using the data bus
– Instruction sent to CIR
Page 10 of 12
Marks
6
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
11
Answer
Any three from:
– Optical media
– Non-volatile
– Offline
– Single (continuous spiral) track
– Data stored using lands / pits
– Read using (red) lasers
– Can be read only (R) or read write (RW)
Question
12
Marks
3
Answer
256 × 200 = 51 200
Marks
3
51 200 × 16
= 102 400
8
102 400
= 100
1024
Answer 100 kB
One mark for correct answer and two marks for correct calculations.
© UCLES 2018
May/June 2018
Page 11 of 12
0478/13
Question
13
© UCLES 2018
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Any six from e.g.:
– Provide access to the internet / dial up / broadband
– Usually charge a monthly fee
– Monitor usage
– Give users an IP address
– Determine bandwidth
– Supports domain names
– Provide security services
– Provide web hosting facilities
– Provide access to Email / Mailbox
– Provides online data storage
Page 12 of 12
May/June 2018
Marks
6
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 6 4 9 5 6 2 2 5 9 6 *
0478/11
COMPUTER SCIENCE
October/November 2018
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (NF/SW) 150228/3
© UCLES 2018
[Turn over
2
1
(a) Computer files can be saved in different file formats.
Four file formats and four file types are given.
Draw a line to match each file format to the most suitable file type.
File format
File type
.jpeg
Text file
.mp3
Image file
.mp4
Audio file
.txt
Video file
[3]
(b) Jamelia wants to store an image file. The image has an 8-bit resolution and is 150 pixels by
100 pixels in size.
Calculate the file size of the image. Give your answer in kilobytes (kB). Show all of your
working.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
File size ........................................................................................................... kB
© UCLES 2018
0478/11/O/N/18
[3]
3
(c) Large files can be compressed to reduce their file size.
Two types of compression that can be used are lossy and lossless.
Explain how a file is compressed using lossless compression.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [3]
(d) The table contains four different file formats that use compression.
Tick () to show whether each file format uses lossy or lossless compression.
File format
Lossy
()
Lossless
()
.jpeg
.mp3
.mp4
.zip
[4]
© UCLES 2018
0478/11/O/N/18
[Turn over
4
2
(a) Six binary or hexadecimal numbers and six denary conversions are given.
Draw a line to connect each binary or hexadecimal number to the correct denary conversion.
Binary or hexadecimal
Denary
01001011
75
4E
78
11011010
157
10011101
167
A7
25
19
218
[5]
(b) Hexadecimal is often used by computer programmers to represent binary values.
Explain why computer programmers may choose to use hexadecimal.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [2]
© UCLES 2018
0478/11/O/N/18
5
3
A logic circuit is shown:
A
X
B
C
(a) Complete the truth table for the given logic circuit.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
(b) Explain the difference between the functions of an AND gate and an OR gate.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [3]
© UCLES 2018
0478/11/O/N/18
[Turn over
6
4
Phishing and pharming are two examples of online security threats to a computer system.
(a) Explain what is meant by phishing and pharming.
Phishing ....................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Pharming ..................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
(b) Identify two other online security threats to a computer system.
Security threat 1 .......................................................................................................................
Security threat 2 .......................................................................................................................
[2]
(c) Give two security measures that can help to protect a computer system from online security
threats.
Security measure 1 ...................................................................................................................
Security measure 2 ...................................................................................................................
[2]
© UCLES 2018
0478/11/O/N/18
7
5
(a) Five storage devices or media are listed in the table.
Tick () to show whether each storage device or media is an example of primary, secondary
or off-line storage.
Storage device or media
Primary
()
Secondary
()
Off-line
()
External HDD
RAM
Internal SSD
ROM
DVD
[5]
(b) Users can store their data on optical storage media.
Explain how data is written to optical storage media.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [4]
© UCLES 2018
0478/11/O/N/18
[Turn over
8
(c) A sports events company uses a digital camera attached to a drone (small flying system), to
video their events from the sky.
The video is stored as it is captured, on a device that is attached to the drone.
(i)
Circle the most suitable type of storage to store the video.
Optical
Magnetic
Solid state
[1]
(ii)
Explain the reasons for your choice in part (c)(i).
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
6
Two examples of output devices are a 3D printer and a 3D cutter.
(a) The table contains four statements about 3D printers and 3D cutters.
Tick () to show which statements apply to each output device, some statements may apply
to both output devices.
3D printer
()
Statement
3D cutter
()
Outputs a physical 3D product
Uses a high powered laser to create the output
Creates 3D prototypes
Uses layers of material to create the output
[4]
(b) Identify the software used to create the computerised designs for 3D printing.
.............................................................................................................................................. [1]
© UCLES 2018
0478/11/O/N/18
9
(c)
A Digital Light Projector (DLP) is another example of an output device.
Describe how a DLP displays an image.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [3]
7
Computers can use different methods of transmission to send data from one computer to another.
Parallel data transmission is one method that can be used.
(a) Explain what is meant by parallel data transmission.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [2]
(b) Give one benefit and one drawback of parallel data transmission, compared to serial data
transmission, over short distances.
Benefit ......................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Drawback ..................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(c) Give one example where parallel data transmission is used.
.............................................................................................................................................. [1]
© UCLES 2018
0478/11/O/N/18
[Turn over
10
8
Kamil correctly answers an examination question about a number of internet terms.
Six different terms have been removed from Kamil’s answer.
Complete the sentences in Kamil’s answer, using the list given. Not all terms in the list need to be
used.
•
•
•
•
•
•
•
•
•
•
•
•
browser
connection
domain name server (DNS)
Internet
Internet Service Provider (ISP)
IP address
MAC address
network
protocol
uniform resource locator (URL)
webpages
hypertext mark-up language (HTML)
A .................................................................................................. is a program that allows a user
to view .................................................................................................. .
An .................................................................................................. is a company that provides a
connection to access the .................................................................................................. .
The main .................................................................................................. that governs the
transmission of data using the Internet is http.
The .................................................................................................. is provided by the network,
and given to each device on the network.
© UCLES 2018
0478/11/O/N/18
[6]
11
9
A sports stadium uses a pressure sensor and a microprocessor to monitor the number of people
entering the sports stadium. For the counter to increment the weight on the pressure sensor must
exceed 5 kg.
Explain how the system uses the pressure sensor and the microprocessor to monitor the number
of people entering.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [5]
10 Personal computers (PCs) use an operating system.
Explain why this type of computer needs an operating system.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..................................................................................................................................................... [4]
© UCLES 2018
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BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2018
0478/11/O/N/18
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
Paper 1
October/November 2018
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2018 series for most
Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level
components.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
© UCLES 2018
[Turn over
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
October/November 2018
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2018
Page 2 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
October/November 2018
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2018
Page 3 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(a)
1(b)
Answer
1 mark for each correct line (to a maximum of 3)
File format
© UCLES 2018
Marks
3
File type
.jpeg
Text file
.mp3
Image file
.mp4
Audio file
.txt
Video file
2 marks for working, 1 mark for correct answer
• 150*100 = 15 000
• 15 000/1024
•
1(c)
October/November 2018
3
14.65kB
Three from:
• a compression algorithm is used
• no data is lost in the process
• repeated words/patterns can be indexed // repeated sections of words/patterns can be indexed // given by example
• The indexed words/patterns can be replaced with numerical values // given by example
Page 4 of 12
3
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(d)
Answer
Marks
1 mark for each correct tick (9)
4
File format
Lossy
(9)
.jpeg
9
.mp3
9
.mp4
9
Lossless
(9)
9
.zip
© UCLES 2018
October/November 2018
Page 5 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(a)
2(b)
© UCLES 2018
Answer
October/November 2018
Marks
1 mark for each correct line (to a maximum of 5)
5
Binary or hexadecimal
Denary
01001011
75
4E
78
11011010
157
10011101
167
A7
25
19
218
Two from:
• It makes the values easier to read/write/understand/debug
• It is a shorter way to represent the values
Page 6 of 12
2
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(a)
3(b)
© UCLES 2018
October/November 2018
Answer
•
•
•
•
Marks
4
4 marks for 8 correct outputs
3 marks for 6 or 7 correct outputs
2 marks for 4 or 5 correct outputs
1 mark for 2 or 3 correct outputs
A
B
C
Working space
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
1
Three from:
• output of AND is 1 if both inputs are 1
• output of AND is 0 if either or both inputs are 0
• output of OR is 1 if either input is 1
• output of OR is 0 if both inputs are 0
• correct example of AND truth table
• correct example of OR truth table
X
3
Page 7 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2018
Marks
4(a)
Four from:
Phishing:
• A legitimate looking email is sent to a user
• The email will encourage the user to click a link/open an attachment
• The link will redirect a user to a legitimate looking webpage (to steal personal data)
Pharming:
• A malicious code is installed on a user’s hard drive/server
• The code will cause a redirection to a legitimate looking webpage (to steal personal data)
4
4(b)
Two from:
• Hacking
• Cracking
• Virus
• Denial of service
• Malware
• Spyware
2
4(c)
Two from:
• Firewall
• Proxy server
• Anti-virus
• Anti-malware
• Anti-spyware
• Username and password
2
© UCLES 2018
Page 8 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(a)
October/November 2018
Answer
Marks
1 mark for the correct tick for each storage
Storage device or media
5
Primary
(9)
Secondary
(9)
9
External HDD
9
RAM
9
Internal SSD
9
ROM
9
DVD
5(b)
Off-line
(9)
Four from:
• The disc is rotated/spun
• Laser beam is used
• The laser beam makes indentations on the surface of the disc/pits and lands
• The data is written in a spiral/concentric tracks
• The pits and lands represent binary values/1s and 0s
• It is called burning data to the disc
4
5(c)(i)
Solid state
1
5(c)(ii)
Two from:
• It has no moving parts so will be durable
• It is small/compact so it can be easily fit onto the device
• It is light so it will not be difficult to lift for the drone
• It can hold the large amount of data needed for the video/film footage
• Uses less power so drone battery will last longer
2
© UCLES 2018
Page 9 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(a)
October/November 2018
Answer
Marks
1 mark for the correct ticks (9) for each statement
4
Statement
Outputs a physical 3D product
3D printer
(9)
3D cutter
(9)
9
9
9
Uses a high powered laser to create the output
Creates 3D prototypes
9
Uses layers of material to create the output
9
9
6(b)
Computer Aided Design/CAD
1
6(c)
Three from:
• Uses a large number of tiny mirrors
• Mirrors are laid out in a grid/matrix
• Each mirror creates a pixel in the image
• Mirrors can tilt toward or away from light source
• The mirrors reflect light toward a (projection) lens
• Colour is produced using a colour wheel // Light passes through colour wheel // filters light into red/green/blue
• Can be used to display an image on a wall/screen
3
© UCLES 2018
Page 10 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
October/November 2018
Answer
Marks
7(a)
1 mark for each correct answer:
• uses several/multiple wires
• transmits multiple bits at a time
2
7(b)
Benefit
1 mark for:
• quicker/faster data transfer
2
Drawback
One from:
• More chance of data being skewed due to bits being sent simultaneously/out of order // less safe transmission as bits
are sent simultaneously/out of order
• More expensive as requires more/several/multiple wires
• More chance of interference as more/several/multiple wires are used (than can create crosstalk)
7(c)
One from:
• Used in integrated circuits
• Used in RAM
• Used in connections to peripheral devices (e.g. printer)
Question
8
© UCLES 2018
Answer
1 mark for each correct answer, in the given order:
• browser
• webpages
• Internet Service Provider (ISP)
• Internet
• protocol
• IP address
1
Marks
6
Page 11 of 12
0478/11
Question
9
Question
10
© UCLES 2018
Cambridge IGCSE – Mark Scheme
PUBLISHED
October/November 2018
Answer
Five from:
• The data is sent to the microprocessor
• The analogue data is converted to digital (using ADC)
• The microprocessor compares the data to a stored value of 5 kg
–
If the value is greater than 5 kg
–
a counter is added to/incremented
• The process is continuous
Answer
Four from:
• It performs a number of basic tasks, including controlling hardware/file handling (any other suitable examples)
• It allows the user to communicate with the computer using hardware // without it the user would not be able to
communicate with the computer using hardware
• It provides the user with a user interface // without it the user would not have a user interface to use
• PC’s are often used to perform many complex tasks at a time
–
the OS is needed to handle this multitasking
–
therefore, it provides the ability to handle interrupts
Page 12 of 12
Marks
5
Marks
4
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 6 2 9 5 6 2 5 4 5 1 *
0478/12
COMPUTER SCIENCE
October/November 2018
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (LEG/SW) 150227/2
© UCLES 2018
[Turn over
2
1
Computers use a character set to convert text into binary.
One character set that can be used is ASCII.
Each letter in ASCII can also be represented as a denary value.
(a) The word BUS has the denary values:
B
U
S
66
85
83
Convert the denary values into 8-bit binary.
66
85
83
[3]
(b) Each letter in ASCII can also be represented as a hexadecimal value.
The word KEY has the 8-bit binary values:
(i)
© UCLES 2018
K
E
Y
01001011
01000101
01011001
Convert the three 8-bit binary values into hexadecimal.
01001011
...............................................
01000101
...............................................
01011001
...............................................
0478/12/O/N/18
[3]
3
(ii)
Give three other uses of hexadecimal notation in computer science.
1 .........................................................................................................................................
2 .........................................................................................................................................
3 .........................................................................................................................................
[3]
(iii)
State two benefits of using hexadecimal notation to represent binary values.
Benefit 1 ............................................................................................................................
...........................................................................................................................................
Benefit 2 ............................................................................................................................
...........................................................................................................................................
[2]
2
A computer uses RAM and ROM to store data.
(a) The table contains three statements about RAM or ROM.
Tick (✓) to show whether each statement describes RAM or ROM.
Statement
RAM
(✓)
ROM
(✓)
Stores the programs and data that are currently in use
Used to boot up the computer when power is turned on
Contents are retained when power is turned off
[3]
(b) Circle the storage category that includes both RAM and ROM.
Primary
Secondary
Off-line
[1]
(c) Explain what is meant by off-line storage.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
© UCLES 2018
0478/12/O/N/18
[Turn over
4
3
A greenhouse uses a system to monitor the conditions that plants need to grow.
The inputs to the system are:
Binary
value
Input
W
T
H
Condition
1
Window is open
0
Window is closed
1
Temperature >=26 °C
0
Temperature <26 °C
1
Humidity >=50%
0
Humidity <50%
The system will sound an alarm when certain conditions are detected.
Alarm (X) will sound (=1) when:
window is closed and temperature >=26 °C
or
temperature <26 °C and humidity >=50%
Draw a logic circuit to represent the system.
W
T
X
H
[5]
© UCLES 2018
0478/12/O/N/18
5
4
(a) Identify three security issues that can put a computer system at risk.
Security issue 1 ........................................................................................................................
Security issue 2 ........................................................................................................................
Security issue 3 ........................................................................................................................
[3]
(b) Explain how a firewall can help to protect a computer system from security issues.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
5
(a) Karina is taking her Computer Science examination. She has three questions to answer
about output devices.
(i)
For the first question she writes the answer:
“It is a high powered laser that cuts materials such as thin metals or wood.”
Identify the output device that Karina is describing.
.......................................................................................................................................[1]
(ii)
For the second question she writes the answer:
“The screen is made up of blocks of red, green and blue pixels. The screen uses layers
of different types of liquid.”
Identify the output device that Karina is describing.
.......................................................................................................................................[1]
(iii)
For the third question she writes the answer:
“It is responsible for powering and moving a motor in machinery, such as a robot arm in
a factory.”
Identify the output device that Karina is describing.
.......................................................................................................................................[1]
© UCLES 2018
0478/12/O/N/18
[Turn over
6
(b) Karina correctly answers another examination question about some more output devices.
Five different terms have been removed from her answer.
Complete the sentences in Karina’s answer, using the list given. Not all terms in the list need
to be used.
•
•
•
•
•
•
•
•
•
•
3D
digital light projector
inkjet
interactive whiteboard
laser
rotating
scanning
sliding
speaker
thermal bubble
An ................................................................................................... allows a user to write on a
surface using a pen, the text and drawings can then be captured and stored for later use.
An ................................................................................................... printer produces a hard
copy of a document using ................................................................................................... and
piezoelectric technology. A ...................................................................................................
printer uses a .............................................................................................. drum, and positive
and negative charges, to produce a hard copy of a document.
© UCLES 2018
0478/12/O/N/18
[5]
7
6
(a) Many programmers write computer programs in high-level languages. The programs need to
be translated into machine code to be read by the computer.
State two types of translator that can be used.
Translator 1 ...............................................................................................................................
Translator 2 ...............................................................................................................................
[2]
(b) Explain two reasons why a computer programmer may choose to write a program in a highlevel language, rather than a low-level language.
Reason 1 ..................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Reason 2 ..................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
(c) Three examples of computer code are given in the table.
Tick (✓) to show whether each example of computer code is High-level language, Assembly
language or Machine code.
Computer code
High-level
language
(✓)
Assembly
language
(✓)
Machine
code
(✓)
10110111
11001100
01011100
FOR X = 1 TO 10
PRINT X
NEXT X
INP X
STA X
LDA Y
© UCLES 2018
[3]
0478/12/O/N/18
[Turn over
8
7
Six internet terms and six definitions are listed.
Draw a line to connect each term to a correct definition.
Internet term
Definition
Browser
A program that allows a user to view
webpages
Internet Service Provider
(ISP)
The main protocol that governs the
transmission of data using the Internet
Hyper Text Transfer Protocol
(HTTP)
The website address that is typed into the
address bar
Uniform Resource Locator
(URL)
An address given to each device on a network.
It is provided by the network
MAC address
A unique address given to a device on a
network. It is provided by the manufacturer
IP address
A company that provides a connection to
access the Internet
[5]
8
Describe the purpose of an interrupt in a computer system.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[4]
© UCLES 2018
0478/12/O/N/18
9
9
(a) Computers can transmit data using different methods.
Describe the three data transmission methods given.
(i)
Serial data transmission
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(ii)
Parallel data transmission
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(iii)
Duplex data transmission
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
© UCLES 2018
0478/12/O/N/18
[Turn over
10
(b) Data can sometimes be corrupted when it is transmitted from one computer to another,
causing errors to be present in the data.
Identify and describe three methods of error detection that could be used to see if an error
has occurred.
Error detection method 1 ..........................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Error detection method 2 ..........................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Error detection method 3 ..........................................................................................................
Description .................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[9]
© UCLES 2018
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11
10 A system uses pH sensors and a microprocessor to help monitor pollution in a river.
The pH of the water should be between 6 and 8. The system outputs an alert if the pH of the water
is not in this range.
Explain how the system uses the pH sensors and the microprocessor to help monitor the pollution.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[5]
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12
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2018
0478/12/O/N/18
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
Paper 1
October/November 2018
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2018 series for most
Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level
components.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
© UCLES 2018
[Turn over
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
October/November 2018
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2018
Page 2 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
October/November 2018
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2018
Page 3 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(a)
Answer
1 mark for each correct 8-bit binary number
October/November 2018
Marks
3
66
0
1
0
0
0
0
1
0
85
0
1
0
1
0
1
0
1
83
0
1
0
1
0
0
1
1
1(b)(i)
1 mark for each correct hexadecimal number
4B
45
59
3
1(b)(ii)
Three from:
• (HTML) colour codes
• Error messages
• MAC addresses
• IP addresses
• Assembly language
• Memory dump
• Locations in memory
3
1(b)(iii)
Two from:
• Easier to read/write/understand (for humans)
• Easier to remember (for humans)
• Short way to represent binary // Uses less screen/display space
• Fewer errors made (in data transcription)
• Easier to debug (for humans)
2
© UCLES 2018
Page 4 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(a)
October/November 2018
Answer
Marks
1 mark for each correct tick (9)
3
Statement
Stores the programs and data that are currently in use
RAM
(9)
ROM
(9)
9
Used to boot up the computer when power is turned on
9
Contents are retained when power is turned off
9
2(b)
Primary
1
2(c)
Two from:
• Non-volatile storage
• Storage that can be disconnected/removed from the computer
• Any suitable example
• Must be (physically) connected to computer to obtain stored data
• Used to store files as a backup
2
© UCLES 2018
Page 5 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3
© UCLES 2018
Answer
1 mark for each correct logic gate, with correct inputs.
October/November 2018
Marks
5
Page 6 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2018
Marks
4(a)
Three from:
• Malware
• Virus // No antivirus
• Denial of service
• Spyware // No antispyware
• Phishing // opening unknown links/emails
• Pharming // opening unknown links/emails (only award once for this alternative)
• Hacking/cracking/unauthorised access // No/weak password // No/weak firewall
• Downloading/Using unknown software
• Not updating software
• Physical issue e.g. computer/door left unlocked
3
4(b)
Four from:
• It examines/monitors/filters traffic into and out of a computer
• It allows a user to set criteria/rules for the traffic
• It checks whether the traffic meets the criteria/rules
• It blocks any traffic that does not meet the criteria/rules // Blocks unauthorised access
• It warns a user of any unauthorised software/access/unauthorised outgoing traffic
• It keeps a log of all traffic (that can be examined)
4
Question
Answer
Marks
5(a)(i)
2D/3D cutter
1
5(a)(ii)
Liquid crystal display // LCD
1
5(a)(iii)
Actuator
1
1 mark for each correct missing word, in the given order:
• interactive whiteboard
• inkjet
• thermal bubble
• laser
• rotating
5
5(b)
© UCLES 2018
Page 7 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(a)
6(b)
© UCLES 2018
Answer
•
•
October/November 2018
Marks
2
Compiler
Interpreter
Four from:
• Closer to human language/English «
• « so it is easier/quicker to read/write/understand
• « so it is easier/quicker to debug the program
• « therefore, less likely to make errors
•
•
•
The program can be used on many different platforms «
« because it is written in source code
« because it is compiled into object code
•
•
They have built-in functions/libraries «
« this saves time when writing the program
•
•
Do not need to manipulate memory addresses directly «
« therefore, specialist knowledge of this is not required
•
•
Only need to learn a single language «
« as this can be used on many different computers
Page 8 of 12
4
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(c)
October/November 2018
Answer
Marks
1 mark for each correct tick (9)
Computer code
3
High-level
language
(9)
Assembly
language
(9)
10110111
11001100
01011100
FOR X = 1 TO 10
PRINT X
NEXT X
9
9
INP X
STA X
LDA Y
© UCLES 2018
Machine
code
(9)
9
Page 9 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7
Answer
1 mark for each correct line (to a maximum of 5)
Browser
© UCLES 2018
October/November 2018
Marks
5
A program that allows a user to view
webpages
Internet Service Provider
(ISP)
The main protocol that governs the
transmission of data using the Internet
Hypertext Transfer Protocol
(HTTP)
The website address that is typed into
the address bar
Uniform Resource Locator
(URL)
An address given to each device on a
network. It is provided by the network
MAC address
A unique address given to a device on
a network. It is provided by the
manufacturer
IP address
A company that provides a connection
to access the Internet
Page 10 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8
Answer
Four from:
• Used to attend to certain tasks/issues
• Used to make sure that vital tasks are dealt with immediately
• The interrupt/signal tells the CPU/processor (that its attention is required)
• A signal that can be sent from a device (attached to the computer)
• A signal that can be sent from software (installed on the computer)
• The interrupt will cause the OS/current process to pause
• The OS/CPU/ISR will service/handle the interrupt
• They have different levels of priority
• After the interrupt is serviced, the (previous) process is continued
• It enables multi-tasking to be carried out on a computer
• A valid example of an interrupt e.g. ‘out of paper’ message for a printer
Question
Answer
October/November 2018
Marks
4
Marks
9(a)(i)
Two from:
• Data is transmitted one bit at a time
• Data is transmitted using a single wire
• Bits arrive in order/sequence
2
9(a)(ii)
Two from:
• Data is transmitted multiple bits at a time/simultaneously
• Data is transmitted using multiple wires
• Bits may arrive out of sequence/skewed (and are reordered)
2
9(a)(iii)
1 mark for each:
• Data is transmitted in both directions
• « at the same time/simultaneously
2
© UCLES 2018
Page 11 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
9(b)
October/November 2018
Answer
Maximum of three marks per error detection method.
1 mark for naming the method, 2 marks for describing it.
Parity (check)
• Odd or even parity can be used
• Bits are added together // 1 bits are counted
• Parity bit added (depending on parity set)
• Parity checked on receipt
• If parity bit is incorrect an error is detected
Marks
9
Checksum
• Calculation performed on data (to get the checksum)
• Checksum sent with data
• Checksum recalculated after transmission
• Comparison made between checksum before and checksum after transmission
• Error detected if checksums are different
Automatic repeat request (ARQ)
• Uses acknowledgement and timeout
• Request is sent (with data) requiring acknowledgement
• If no response/acknowledgment within certain time frame data package is resent
• When data received contains an error a request is sent (automatically) to resend the data
• The resend request is repeatedly sent until packet is received error free/limit is reached/acknowledgement received
Question
10
© UCLES 2018
Answer
Five from:
• The sensor sends data to the microprocessor
• The analogue data is converted to digital (using ADC)
• The microprocessor compares the reading to the set range/stored values/stored data (6 to 8) «
– « If the reading is >8 or <6 / outside range «
o « the microprocessor sends a signal to output the alert
• The process is continuous/repeated
Page 12 of 12
Marks
5
Cambridge International Examinations
Cambridge International General Certificate of Secondary Education
* 9 6 3 2 1 2 6 1 4 9 *
0478/13
COMPUTER SCIENCE
October/November 2018
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (KN/SW) 150225/2
© UCLES 2018
[Turn over
2
1
There are six output devices and six descriptions shown.
Draw a line to connect each output device to the most appropriate description.
Device
Description
Uses a high-intensity beam
of light shone through three layers
of changing pixels
Laser Printer
Uses millions of micro mirrors to
reflect light through a lens
LCD Projector
Digital Light Projector
(DLP)
Uses plastic, resin or
powdered metal to generate a
physical output
Inkjet Printer
Uses a static electric charge
on a rotating drum to
generate a physical output
3D Printer
Uses liquid ink to generate
a physical output
2D Cutter
Uses a high-power laser to
generate a physical output
[5]
© UCLES 2018
0478/13/O/N/18
3
2
Parity checks and Automatic Repeat reQuests (ARQ) can be used to check for errors during data
transmission and storage.
(a) A system uses even parity. Write the appropriate parity bit for each byte.
Parity Bit
1
0
1
0
0
1
1
1
0
1
1
1
1
1
1
0
1
0
0
0
1
[2]
(b) Explain how Automatic Repeat reQuests (ARQ) are used in data transmission and storage.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(c) State one other method that could be used to check for transmission errors.
...............................................................................................................................................[1]
3
An elevator (lift) has a maximum weight limit of 2400 kg. The weight carried is monitored by a
sensor and a microprocessor.
Describe how the sensor and the microprocessor are used to make sure the maximum weight
limit is not exceeded.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[6]
© UCLES 2018
0478/13/O/N/18
[Turn over
4
4
The MAC address of a device is represented using hexadecimal.
A section of a MAC address is shown. Each pair of hexadecimal digits is stored using 8-bit binary.
(a) Complete the table to show the 8-bit binary equivalents for the section of MAC address. The
first number has already been converted.
6A
FF
08
93
01101010
[3]
(b) Explain why data is stored as binary in computers.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
5
Data can be transferred using half-duplex serial transmission.
(a) Describe serial transmission.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(b) Give one application of serial data transmission.
...................................................................................................................................................
...............................................................................................................................................[1]
(c) Describe half-duplex data transmission.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
© UCLES 2018
0478/13/O/N/18
5
6
Sarah stores data electronically.
Describe three methods that she could use to avoid loss of stored data.
Method 1 ..........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Method 2 ..........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Method 3 ..........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2018
0478/13/O/N/18
[Turn over
6
7
David is writing a program using a high-level language. The program will be published and sold for
profit.
(a) David uses an interpreter when creating the computer program.
State three features of an interpreter.
Feature 1 ..................................................................................................................................
...................................................................................................................................................
Feature 2 ..................................................................................................................................
...................................................................................................................................................
Feature 3 ..................................................................................................................................
...................................................................................................................................................
[3]
(b) David compiles the program when he has completed it.
Explain two benefits of compiling the program.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2018
0478/13/O/N/18
7
(c) David needs to send a large section of the programming code as an email attachment.
He uses lossless compression to reduce the file size.
Explain how the file size is reduced.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
© UCLES 2018
0478/13/O/N/18
[Turn over
8
8
Alice enters a URL into a web browser to access a webpage.
(a) State what URL represents.
U ........................................... R ........................................... L ........................................... [1]
(b) Explain how the web browser uses the URL to access the webpage.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
9
Describe two differences between Read Only Memory (ROM) and Random Access Memory
(RAM).
Difference 1 .......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Difference 2 ......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
© UCLES 2018
0478/13/O/N/18
9
10 A logic circuit is shown:
A
X
B
C
(a) Complete the truth table for the given logic circuit.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2018
0478/13/O/N/18
[Turn over
10
(b) Draw a logic circuit corresponding to the logic statement:
X = 1 if ((A is 1 AND B is 1) AND (A is 1 OR C is NOT 1)) OR (B is 1 AND C is NOT 1)
A
B
X
C
[6]
11
The fetch-execute cycle make use of registers.
(a) Describe the role of the Program Counter (PC).
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(b) Describe the role of the Memory Data Register (MDR).
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
© UCLES 2018
0478/13/O/N/18
11
12 Explain the difference between a Musical Instrument Digital Interface (MIDI) file and a MP3 file.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
......................................................................................................................................................[4]
13 State which types of storage device or media would be most suitable for these scenarios.
For each device or media, justify your choice.
(a) Creating a backup of 150 GB of data.
...................................................................................................................................................
Justification ...............................................................................................................................
...................................................................................................................................................
[2]
(b) Storing applications on a tablet device.
...................................................................................................................................................
Justification ...............................................................................................................................
...................................................................................................................................................
[2]
(c) Storing a 1200 MB high-definition promotional movie about a new car. The movie is to be
given to people who are interested in buying a new car.
...................................................................................................................................................
Justification ...............................................................................................................................
...................................................................................................................................................
[2]
© UCLES 2018
0478/13/O/N/18
12
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International
Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after
the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2018
0478/13/O/N/18
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
Paper 1
October/November 2018
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2018 series for most
Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level
components.
This syllabus is approved for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 13 printed pages.
© UCLES 2018
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
October/November 2018
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2018
Page 2 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
October/November 2018
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2018
Page 3 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
Marks
1 mark for each correct line, maximum 5 marks
5
Device
Description
Laser Printer
Uses a high-intensity beam
of light shone through three
layers of changing pixels
LCD Projector
© UCLES 2018
October/November 2018
Uses millions of micro
mirrors to reflect light
through a lens
Digital Light Projector
(DLP)
Uses plastic, resin or
powdered metal to generate
a physical output
Inkjet Printer
Uses a static electric charge
on a rotating drum to
generate a physical output
3D Printer
Uses liquid ink to generate a
physical output
2D Cutter
Uses a high-power laser to
generate a physical output
Page 4 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(a)
October/November 2018
Answer
Marks
2 marks for 3 correct bits, 1 mark for 2 correct bits
2
Parity Bit
0
1
0
1
0
0
1
1
0
1
0
1
1
1
1
1
1
1
0
1
0
0
0
1
2(b)
Two from:
• Set of rules for controlling error checking/detection // it’s an error detection method // used to detect errors
• Uses acknowledgement and timeout
• Request is sent (with data) requiring acknowledgement
• If no response/acknowledgment within certain time frame data package is resent
• When data received contains an error a request is sent (automatically) to resend the data
• The resend request is repeatedly sent until packet is received error free/limit is reached/acknowledgement received
2
2(c)
Checksum
1
Question
3
© UCLES 2018
Answer
Six from:
• A pressure sensor is used
• The sensor sends data/signals to the microprocessor
• Data is converted to digital format
• Microprocessor compares data value against set value
• If value <= 2400 Kg/under weight limit lift is permitted to operate
• If value > 2400 Kg/over weight limit signal is sent from the microprocessor to deliver warning message to
passengers
• If value > 2400 Kg signal is sent from the microprocessor to lift mechanism to stop lift operating
• Weight continuously monitored
Page 5 of 13
Marks
6
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)
Answer
•
•
3
11111111
5(b)
5(c)
© UCLES 2018
00001000
Answer
•
•
Marks
2
Bits sent one at a time
Uses a single wire
USB / SATA / Wifi /PCI Express / Any appropriate serial device
•
•
10010011
2
Computers use switches / logic gates
Only uses 2 states / On or Off / 1 or 0
Question
5(a)
Marks
1 mark for each correct conversion
01101010
4(b)
October/November 2018
1
2
Data is transferred in two directions
Data is sent in only one direction at a time
Page 6 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6
Answer
1 mark for method name, 1 mark for description e.g.
Marks
6
Backups
• Make a copy of the data
• Copy stored away from main computer
• Data can be restored from backup
Anti-virus
• Scans computer for viruses
• Software to detect/remove viruses
• Can prevent data being corrupted by viruses
Firewall
• Hardware or software that monitors network traffic
• To help prevent hackers gaining access / deleting data
Password/Biometrics
• To help protect files / computer from unauthorised access
Restricted access
• To stop users downloading/installing software that could harm
Verification
• Message e.g. to ask if definitely want to delete
Physical methods
• Locks/alarms/CCTV to alert/deter unauthorised access
© UCLES 2018
October/November 2018
Page 7 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2018
Marks
7(a)
Three from:
• It is a translator
• Translates (high level language) to low level language
• Executes one line at a time
• Translates source code line by line
• Runs error diagnostic
• Produces error messages to tell user location of error
• Stops execution when encounters errors
• Continues translating when an error is fixed
3
7(b)
Four from (Max three per benefit):
4
7(c)
© UCLES 2018
•
•
•
Produces executable file
this creates a smaller file size
more saleable
•
•
Program will be machine independent / portable
this means it can be used on any hardware
•
•
•
No need for compiler to run executable file
this means it will be quicker to run
customers can just execute the program
•
•
Source code cannot be accessed
therefore, code cannot be stolen / plagiarised
Three from:
• Uses compression algorithm / by example e.g. RLE
• Repeating words / phrases / patterns identified
•
replaced with value
• File / dictionary / index of phrases created
• Index will store word/phrase with value
Page 8 of 13
3
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2018
Marks
8(a)
Uniform Resource Locator
1
8(b)
Four from:
• The web browser sends URL to DNS
• DNS stores an index of URL and matching IP address
• DNS searches for URL to obtain the IP address
• IP address sent to web browser, (if found)
• Web browser sends request to IP of webserver
• Webserver sends web page to web browser
• Web browser interprets HTML to display web page
• If URL not found DNS returns error
4
Question
9
© UCLES 2018
Answer
Four from:
•
•
ROM is permanent
RAM is temporary
•
•
ROM is non-volatile
RAM is volatile
•
•
ROM is read only
RAM can have read/write operations
•
•
ROM holds instructions for boot up
RAM holds files / instructions in use
Marks
4
Page 9 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
10(a)
© UCLES 2018
Answer
October/November 2018
Marks
4 marks for 8 correct outputs
3 marks for 6 or 7 correct outputs
2 marks for 4 or 5 correct outputs
1 mark for 2 or 3 correct outputs
4
A
B
C
X
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
0
1
1
1
0
Page 10 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
10(b)
Answer
1 mark per correct gate with correct inputs.
Question
October/November 2018
Marks
6
Answer
Marks
11(a)
•
•
Holds address of next/current instruction
to be fetched/processed/executed
2
11(b)
•
•
Stores data/instruction that is in use «
from address in MAR
2
© UCLES 2018
Page 11 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
12
Answer
Four from (Max three from each):
MP3
• Digital recording of sound
• Produced by recording software / microphone
• Used when distributing sound files
• Compressed file format
MIDI
•
•
•
•
•
•
© UCLES 2018
Marks
4
Instructions of how to make sound
Non-audio recording
File created using digital musical instruments
Produced by synthesizer
Used when composing music
Individual notes/instruments can be changed
Question
13(a)
October/November 2018
Answer
1 mark for storage, 1 mark for justification
Marks
2
•
External/Removable HDD // External/Removable SSD // Large capacity USB Flash Drive
•
•
•
Backups must be stored separately
Will hold sufficient data
Faster write abilities (SSD/USB drive only)
Page 12 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
13(b)
13(c)
© UCLES 2018
Answer
1 mark for storage, 1 mark for justification
•
SSD // SD card // Flash memory
•
•
•
•
•
•
Small physical size
Lightweight
Low heat production
Low power consumption
It’s quiet
Fast read/write times
October/November 2018
Marks
2
1 mark for storage, 1 mark for justification
2
•
DVD // Blu-ray // USB Flash Drive // SD card
•
•
•
•
Easy to distribute
Small in size
Cheap to buy
Universal storage therefore compatible with many devices
Page 13 of 13
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
* 6 6 7 7 5 3 2 7 6 4 *
0478/12
COMPUTER SCIENCE
February/March 2019
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (KN/FC) 168931/3
© UCLES 2019
[Turn over
2
1
www.dynamicpapers.com
(a) Elle has a file stored on her computer that is 20 MB in size. Jordan has a file that is 10 GB in
size.
Tick (3) to show which is the larger file.
File size
Tick
(3)
20 MB
10 GB
[1]
(b) Bob has a file stored on his computer that is 3500 kB in size. Gerty has a file that is 3 MB in
size.
Tick (3) to show which is the larger file.
File size
Tick
(3)
3500 kB
3 MB
[1]
2
Many computer systems have an input device and an output device.
(a) (i)
State what is meant by an input device.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
Give an example of an input device.
..................................................................................................................................... [1]
(b) (i)
State what is meant by an output device.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
Give an example of an output device.
..................................................................................................................................... [1]
© UCLES 2019
0478/12/F/M/19
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3
3
(a) A long distance running race uses an electronic counter that counts each competitor who
finishes the race.
The count is stored as binary in a 12-bit register.
A denary value of the count is displayed on a screen above the finish line.
(i)
The screen currently displays:
0
0
3
9
State the binary value that is currently stored to display the count shown.
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
More competitors cross the finish line and the screen now displays:
0
3
5
0
State the binary value that is currently stored to display the count shown.
...........................................................................................................................................
..................................................................................................................................... [2]
(iii)
At the end of the race the binary value stored is:
011011000111
Give the denary value that would be displayed on the screen at the end of the race.
Show your working.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
Screen display:
[2]
© UCLES 2019
0478/12/F/M/19
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(b) Sensors are used at the finish line to identify the number of competitors who finish the race.
(i)
Identify two different sensors that could be used to identify the number of competitors.
Sensor 1 .............................................................................................................................
Sensor 2 .............................................................................................................................
[2]
(ii)
The sensors are used with a microprocessor to count how many competitors finish the
race.
Explain how the sensor and the microprocessor are used.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [6]
© UCLES 2019
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4
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Darius is writing a computer program that allows binary values to be calculated.
Darius chooses to write the program in a high-level language rather than a low-level language.
(a) Explain why Darius chooses to write the program in a high-level language.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(b) Darius will use a translator to translate the program. He could use a compiler or an interpreter.
Five statements are given about compilers and interpreters.
Tick (3) to show if the statement applies to a Compiler or an Interpreter. Statements may
apply to both.
Compiler
(3)
Statement
Interpreter
(3)
A report of errors is produced at the end of translation.
The program is translated one line at a time.
The program is translated from high-level language into
machine code.
An executable file is produced.
The program will not run at all if an error is detected.
[5]
© UCLES 2019
0478/12/F/M/19
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Darius is sending several programs that he has created to his friend Selma.
(c) He wants to compress the files to send them as he needs to attach them to an email.
Darius tells Selma he is going to use lossy compression. Selma tells him that he should use
lossless instead.
Explain why Selma tells Darius to use lossless compression instead of lossy.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(d) Errors can occur when data is transmitted, stored or entered into a system.
Darius could use an error detection method to find whether errors have occurred.
One error detection method he could use is a checksum.
(i)
Describe how a checksum detects errors.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [5]
© UCLES 2019
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7
(ii)
www.dynamicpapers.com
State three other error detection methods that Darius could use.
Method 1 ............................................................................................................................
Method 2 ............................................................................................................................
Method 3 ............................................................................................................................
[3]
© UCLES 2019
0478/12/F/M/19
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5
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Consider the following logic statement:
X = 1 if ((A is 1 NAND C is 1) NOR A is NOT 1) OR (B is 1 AND C is NOT 1)
(a) Draw a logic circuit that represents the given logic statement. Your logic gates must have a
maximum of two inputs. Do not simplify the logic statement.
A
B
X
C
[6]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2019
0478/12/F/M/19
9
6
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Nadia purchases a printer to print out her homework.
She connects the printer to her computer using USB.
(a) Explain what is meant by USB.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) Nadia’s printer uses powdered toner rather than liquid ink.
(i)
State the type of printer Nadia has purchased.
..................................................................................................................................... [1]
(ii)
Give two benefits of using this type of printer.
Benefit 1 .............................................................................................................................
...........................................................................................................................................
Benefit 2 .............................................................................................................................
...........................................................................................................................................
[2]
(iii)
Give one drawback of using this type of printer.
Drawback 1 ........................................................................................................................
..................................................................................................................................... [1]
© UCLES 2019
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10
(c) Nadia uses several types of computer storage for her homework and other projects.
(i)
Five examples of computer storage are given.
Tick (3) to show if the computer storage is Primary, Secondary or Off-line.
Storage example
Primary
(3)
Secondary
(3)
Off-line
(3)
Solid state drive (SSD)
Blu-ray disc
USB flash memory
Random access memory (RAM)
Read only memory (ROM)
[5]
(ii)
Nadia is considering purchasing a magnetic storage device.
Describe how a magnetic storage device stores data.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [6]
© UCLES 2019
0478/12/F/M/19
11
(iii)
www.dynamicpapers.com
Give two advantages of using a magnetic storage device rather than a solid state storage
device.
Advantage 1 .......................................................................................................................
...........................................................................................................................................
Advantage 2 .......................................................................................................................
...........................................................................................................................................
[2]
7
Arya regularly uses the Internet as a research tool for her school projects.
Identify and describe three risks to Arya’s computer when she is using the Internet for research.
Risk 1 ................................................................................................................................................
Description ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Risk 2 ................................................................................................................................................
Description ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Risk 3 ................................................................................................................................................
Description ........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
© UCLES 2019
0478/12/F/M/19
12
www.dynamicpapers.com
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019
0478/12/F/M/19
www.dynamicpapers.com
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
Paper 1
March 2019
MARK SCHEME
Maximum Mark: 50
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the March 2019 series for most
Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level
components.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 9 printed pages.
© UCLES 2019
[Turn over
Cambridge IGCSE – Mark Scheme
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PUBLISHED
Generic Marking Principles
These general marking principles must be applied by all examiners when marking candidate answers.
They should be applied alongside the specific content of the mark scheme or generic level descriptors
for a question. Each question paper and mark scheme will also comply with these marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is
given for valid answers which go beyond the scope of the syllabus and mark scheme, referring
to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these
features are specifically assessed by the question as indicated by the mark scheme. The
meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions
or in the application of generic level descriptors.
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question
(however; the use of the full mark range may be limited according to the quality of the candidate
responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should
not be awarded with grade thresholds or grade descriptors in mind.
© UCLES 2019
Page 2 of 9
0478/12
March 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
1(a)
File size
Marks
Tick
(9)
1
20 MB
9
10 GB
1(b)
File size
Tick
(9)
1
9
3500 kB
3 MB
Question
Answer
Marks
2(a)(i)
−
2(a)(ii)
One from e.g.:
− Keyboard
− Mouse
− Microphone
− Sensor
− Touch screen
1
2(b)(i)
−
1
2(b)(ii)
One from e.g. :
− Monitor
− Speaker
− Headphones
− Printer
(A device that allows) data to be entered (into a computer system)
(A device that allows the user to) view/hear the data (that has been entered into a computer system)
© UCLES 2019
1
1
Page 3 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(a)(i)
Answer
−
March 2019
www.dynamicpapers.com
Marks
2
000000100111
1 mark 1 mark
3(a)(ii)
−
2
000101011110
1 mark 1 mark
3(a)(iii)
1 mark for working, 1 mark for correct answer
− 1024 + 512 + 128 + 64 + 4 + 2 + 1
− 1735
2
3(b)(i)
Two from:
− Pressure sensor
− Light sensor
− Motion sensor
− Magnetic field (can be used if competitors are wearing a compatible chip)
2
3(b)(ii)
−
−
−
−
−
−
6
Sensor sends signal to microprocessor
Signal is analogue and is converted to digital (using ADC)
Data is compared to stored value // Check for signal
If data does not match / is out of range/ in range // signal detected
counter is incremented by 1
Continuous process
© UCLES 2019
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March 2019
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
Marks
4(a)
Two from:
− Closer to English statements / human language
− Easier / quicker to write / read / understand / remember
− Easier / quicker to debug
− Less likely to make errors
− One line of code can carry out multiple commands
− Portable language
2
4(b)
1 mark for correct tick(s) for each statement
5
Statement
Compiler Interpreter
A report of errors is produced at the end of translation
9
9
The program is translated one line at a time
The program is translated from high-level language into machine code
9
An executable file is produced
9
The program will not run at all if an error is detected
9
9
4(c)
−
−
−
−
Lossy would remove data
Lossless does not remove data // No data can be lost
Can be restored to original state
otherwise will not run / work correctly
4
4(d)(i)
−
−
−
−
−
Sending device creates value from calculation on data // By example
Value is transmitted with the data
Receiving device performs same calculation
Values are compared after transmission // If values do not match
an error is detected
5
© UCLES 2019
Page 5 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4d(ii)
Answer
−
−
−
Marks
3
Parity check
Check digit
Automatic repeat request
Question
5(a)
March 2019
www.dynamicpapers.com
Answer
Marks
1 mark for each correct logic gate with correct input(s)
6
A
B
X
C
© UCLES 2019
Page 6 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(b)
Answer
6(b)(i)
Marks
4 marks for 8 correct outputs
3 marks for 6/7 correct outputs
2 marks for 4/5 correct outputs
1 mark for 2/3 correct outputs
Question
6(a)
March 2019
www.dynamicpapers.com
4
A
B
C
Working space
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
1
Answer
X
Marks
Three from:
− Universal Serial Bus
− Data transmission method
− Uses serial transmission // bits of data are sent one at a time
− Universal standard // common interface
3
−
1
Laser printer
© UCLES 2019
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March 2019
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
Marks
6(b)(ii)
Two from:
− Cheaper printing cost per page
− It prints at a faster speed
− It prints text at a high quality
− Colour fast
2
6(b)(iii)
One from:
− Expensive to purchase printer
− Toner is expensive
− Print images at a lower quality
− Can be quite large in size
1
6(c)(i)
1 mark per each correct tick
5
Storage example
Primary
Off-line
9
Solid state drive (SSD)
© UCLES 2019
Secondary
Blu-ray disc
9
USB flash memory
9
Random access memory (RAM)
9
Read only memory (ROM)
9
Page 8 of 9
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(c)(ii)
March 2019
www.dynamicpapers.com
Answer
Six from:
− Storage device has platters
− Platters/disk divided into tracks
− Storage platter / disk is spun
− Has a read/write arm that moves across storage media
− Read/writes data using electromagnets
− Uses magnetic fields to control magnetic dots of data
− Magnetic field determines binary value
Marks
6
NOTE: Marks can be awarded for an alternative description e.g. magnetic tape
6(c)(iii)
−
−
Magnetic is cheaper per unit of data
Magnetic has more longevity // Magnetic can perform more read/write cycles
Question
7
Answer
For each of three risks
Naming the risk – 1 mark, describing the risk – 1 mark:
Marks
6
−
−
−
Hacking
when a person tries to gain unauthorised access to a computer system
data can be deleted/corrupted by hacker
−
−
−
Malware
a software program designed to damage data / disrupt the computer system
replicates itself and fills the hard disk
−
−
Virus
a program that replicates itself to damage / delete files
NOTE: Multiple kinds of malware can be awarded if listed and given a matching description e.g. trojan horse, worm.
© UCLES 2019
2
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
* 8 2 2 6 4 6 8 0 1 1 *
0478/11
COMPUTER SCIENCE
May/June 2019
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (LK) 172696/2
© UCLES 2019
[Turn over
2
1
www.dynamicpapers.com
Hexadecimal is used for MAC addresses.
Part of a MAC address is given:
97 – 5C – E1
Each pair of digits is stored as binary in an 8-bit register.
(a) Show what the binary register stores for each pair of the given digits.
97
5C
E1
[6]
(b) Explain what is meant by a MAC address.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(c) Give two other examples where hexadecimal can be used.
Example 1 .................................................................................................................................
...................................................................................................................................................
Example 2 .................................................................................................................................
...................................................................................................................................................
[2]
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Rajesh creates a logic circuit.
He uses three different logic gates in his circuit. Each logic gate has a maximum of two inputs.
He describes the logic of each gate.
(a) “The only time the output will be 1 is when both inputs are 1.”
State the single logic gate ...................................................
Draw the single logic gate:
[2]
(b) “The only time the output will be 1 is when both inputs are 0.”
State the single logic gate ...................................................
Draw the single logic gate:
[2]
(c) “The only time the output will be 0 is when both inputs are 1.”
State the single logic gate ...................................................
Draw the single logic gate:
[2]
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Five descriptions of different input or output devices are given in the table.
Complete the table by stating the name of each input or output device.
Description
Name of device
This is an input device that works by shining a light
onto the surface of a document. The light source is
automatically moved across the document and the
reflected light is captured by mirrors and lenses.
This is an input device where a laser or a light source is
moved across an object. The width, height and depth of
the object are measured to allow a model to be created.
This is a large input device that is usually fixed to a
wall. A user can calibrate the device to make sure the
sensors align with a projected image. The user can use
either their finger or a special pen to make selections.
...................................................
...................................................
...................................................
This is an output device that uses many small mirrors to
reflect light towards a lens. This will display an image.
...................................................
This is an output device that creates an object by
building layer upon layer of material.
...................................................
[5]
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(a) Lola is concerned about the risks to her computer when using the Internet.
She wants to use some security methods to help protect her computer from the risks.
Identify a security method she could use for each of the following risks. Each security method
must be different.
Describe how each security method will help protect Lola’s computer.
(i)
Computer virus
Security method ................................................................................................................
Description ........................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
(ii)
Hacking
Security method ................................................................................................................
Description ........................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
(iii)
Spyware
Security method ................................................................................................................
Description ........................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
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(b) Lola is also concerned that the data she stores could be subject to accidental damage or
accidental loss.
(i)
State three ways that the data Lola stores could be accidentally damaged or accidentally
lost.
1 ........................................................................................................................................
...........................................................................................................................................
2 ........................................................................................................................................
...........................................................................................................................................
3 ........................................................................................................................................
...........................................................................................................................................
[3]
(ii)
Give two methods that Lola could use to help keep her data safe from accidental damage
or accidental loss.
1 ........................................................................................................................................
...........................................................................................................................................
2 ........................................................................................................................................
...........................................................................................................................................
[2]
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The following text is stored as a text file:
She sells sea shells on the seashore. The shells that she sells are sea shells I am sure.
Explain how lossless compression would compress this file.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [5]
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A law company holds a lot of sensitive data about its clients.
(a) It currently requires employees to enter a username and a password to log-in to an account.
Each password must be 8 letters.
The company wants to increase the security of the log-in system.
Identify two improvements the company could use to make the log-in system more secure.
Explain how each improvement increases security.
Improvement 1 ..........................................................................................................................
...................................................................................................................................................
Explanation ...............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Improvement 2 ..........................................................................................................................
...................................................................................................................................................
Explanation ...............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
(b) The law company wants to purchase a new file server.
The company can purchase a server with either solid state storage or magnetic storage. After
discussion, it decides to purchase a file server with magnetic storage.
Explain why the company chose magnetic storage rather than solid state storage.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
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(c) The law company also uses optical storage.
Give three different examples of optical storage.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
7
Annie writes a paragraph of text as an answer to an examination question about programming
languages.
Using the list given, complete Annie’s answer by inserting the correct six missing terms. Not all
terms will be used.
•
•
•
•
•
•
•
•
•
•
Assembly
Converter
Denary
Hexadecimal
High-level language
Low-level language
Machine Code
Source Code
Syntax
Translator
The structure of language statements in a computer program is called the
....................................................................... . A programming language that uses natural
language statements is called a ....................................................................... . When programs
are written in this type of language they need a ....................................................................... to
convert them into ....................................................................... .
A programming language that is written using mnemonic codes is called a
....................................................................... . An example of this type of language is
....................................................................... language.
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An art gallery has a website that is used to display and sell art.
(a) The gallery uses Secure Socket Layer (SSL) to provide a secure connection when selling art.
Describe the process of SSL and how it provides a secure connection.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
(b) The art gallery also uses a firewall.
Six statements are given about firewalls.
Tick (3) to show if the statement is True or False.
Statement
True
(3)
False
(3)
Firewalls are only available as hardware devices
Firewalls allow a user to set rules for network traffic
Firewalls will automatically stop all malicious traffic
Firewalls only examine traffic entering a network
Firewalls encrypt all data that is transmitted around a network
Firewalls can be used to block access to certain websites
[6]
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(c) The art gallery is concerned about computer ethics relating to its website.
Explain what is meant by computer ethics and why the art gallery is concerned about
computer ethics.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
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BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
Paper 1
May/June 2019
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2019 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and
some Cambridge O Level components.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 14 printed pages.
© UCLES 2019
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2019
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These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
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Cambridge IGCSE – Mark Scheme
PUBLISHED
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GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
Marks
1(a)
6
97
1
0
0
1
0
1 mark
5C
0
1
1
1
0
1
1
© UCLES 2019
1
1
0
0
0
1
1 mark
1
0
0
1 mark
1(b)
1
1 mark
1 mark
E1
1
0
1 mark
Four from:
• Media Access Control (address)
• Used to identify a device
• It is a unique (address)
• It is a static address // It does not change
• It is set by the manufacturer
• The first part is the manufacturer ID/number/identifies the manufacturer
• The second part is the serial number/ID
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(c)
Answer
Two from e.g.:
•
•
•
•
•
•
•
•
Colour codes // Colour in HTML / CSS
Error messages
Locations in memory
Memory dump // debugging
IP address
ASCII // Unicode
Assembly language
URL
Answer
1 mark for correct name, 1 mark for correct gate symbol
−
2(b)
© UCLES 2019
Marks
2
AND
1 mark for correct name, 1 mark for correct gate symbol
−
Marks
2
Question
2(a)
May/June 2019
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NOR
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0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(c)
Answer
2
NAND
Question
© UCLES 2019
Marks
1 mark for correct name, 1 mark for correct gate symbol
−
3
May/June 2019
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Answer
Marks
1 mark for each correct device
5
Description of input or output device
Name of device
This is an input device that works by shining a light onto the surface of a document. The
light source is automatically moved across the document and the reflected light is captured
by mirrors and lenses.
2D Scanner
This is an input device where a laser or a light source is moved across an object. The
width, height and depth of the object are measured to allow a model to be created.
3D scanner
This is a large input device that is usually fixed to a wall. A user can calibrate the device to
make sure the sensors align with a projected image. The user can use either their finger or
a special pen to make selections.
Interactive
whiteboard
This is an output device that uses many small mirrors to reflect light towards a lens. This
will display an image.
Projector
This is an output device that creates an object by building layer upon layer of material.
3D printer
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)(i)
Answer
1 mark for security method, 2 marks for description
Marks
3
Anti-virus (software) // Anti-malware (software)
• Scans the computer system (for viruses)
• Has a record of known viruses
• Removes/quarantines any viruses that are found
• Checks data before it is downloaded
• « and stops download if virus found/warns user may contain virus
Firewall // Proxy server
• Monitors traffic coming into and out of the computer system
• Checks that the traffic meets any criteria/rules set
• Blocks any traffic that does not meet the criteria/rules set // set blacklist/whitelist
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)(ii)
May/June 2019
www.dynamicpapers.com
Answer
1 mark for security method, 2 marks for description
3
Firewall // proxy server
• Monitors traffic coming into and out of the computer system
• Check that the traffic meets any criteria/rules set
• Blocks any traffic that does not meet the criteria/rules set // set blacklist/whitelist
NOTE: Cannot be awarded if already given in 4(a)(i)
Passwords
• Making a password stronger // by example
• Changing it regularly
• Lock out after set number of attempts // stops brute force attacks // makes it more difficult to guess
Biometrics
• Data needed to enter is unique to individual
• « therefore very difficult to replicate
• Lock out after set number of attempts
Two-step verification // Two-factor authentication
• Extra data is sent to device, pre-set by user
• « making it more difficult for hacker to obtain it
• Data has to be entered into the same system
• « so if attempted from a remote location, it will not be accepted
© UCLES 2019
Marks
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)(iii)
Answer
1 mark for security method, 2 marks for description
May/June 2019
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Marks
3
Anti-spyware software // Anti-malware (software)
• Scans the computer for spyware
• Removes/quarantines any spyware that is found
• Can prevent spyware being downloaded
NOTE: Anti-malware (software) cannot be awarded if already given in 4(a)(i)
Drop-down boxes // onscreen/virtual keyboard
• Means key logger cannot collect data // key presses cannot be recorded
• « and relay it to third party
Two-step verification // Two-factor authentication
• Extra data is sent to device, pre-set by user
• « making it more difficult for hacker to obtain it
• Data has to be entered into the same system
• « so if attempted from a remote location, it will not be accepted
NOTE: Cannot be awarded if already given in 4(a)(ii)
Firewall // proxy server
• Monitors traffic coming into and out of the computer system
• Check that the traffic meets any criteria/rules set
• Blocks any traffic that does not meet the criteria/rules set // set blacklist/whitelist
NOTE: Cannot be awarded if already given in 4(a)(i) or 4(a)(ii)
4(b)(i)
© UCLES 2019
Three from:
• Human error e.g. accidentally deleting a file
• Hardware failure
• Physical damage e.g. fire/flood
• Power failure // power surge
• Misplacing a storage device
3
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Question
4(b)(ii)
Question
5
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Two from:
• Back data up
• Use surge protection
• Keep data in a fireproof / waterproof / protective case
• Use verification methods (for deleting files)
• Following correct procedure e.g. ejecting offline devices / regularly saving
Answer
Five from:
• A (compression) algorithm is used
• No data is removed in the process // original file can be restored
• Repeated words (are identified) // Patterns in the data (are identified)
• « and are indexed/put into a table // by example
• « and are replaced with their index // by example
• « and their positions are stored (in the table) // by example
• « and the number of times the word/pattern appears is stored (in the table) // by example
NOTE: Other valid methods of lossless compression can be awarded marks
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Marks
2
Marks
5
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(a)
© UCLES 2019
Answer
Four from (max 2 marks per improvement):
• Make the password require more characters
• Makes the password harder to crack/guess
• More possible combinations for the password
May/June 2019
www.dynamicpapers.com
Marks
4
•
•
•
Make the password require different types of characters
Makes the password harder to crack/guess
More possible combinations for the password
•
•
Use a biometric device
Hard to fake a person’s biological data // data is unique
•
•
•
•
•
Two-step verification // Two factor-authentication
Adds an additional level to hack
Have to have the set device for the code to receive it
Drop-down boxes // onscreen keyboard
To prevent passwords being obtained using keylogger
•
•
Request random characters
Won’t reveal entire password
•
•
•
Set number of password attempts
Will lock account if attempting to guess
Will stop brute-force attacks
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(b)
6(c)
© UCLES 2019
Answer
Four from (max 3 marks for benefits only, without an explanation):
• More read/write cycles (over its lifetime) // greater longevity «
• « likely to be a lot of read/write functions each day
• Read/write speed is sufficient «
• « even though it is slower than solid-state
• Cheaper per unit of data stored «
• « better value for the company to purchase
• « so the law company can afford to buy a server with greater storage capacity
• No requirement for portability «
• « as a server, it does not need to be moved
• Trusted technology «
• « it has been traditionally used for many years
•
•
•
May/June 2019
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Marks
4
3
DVD
CD
Blu-ray
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7
Question
8(a)
© UCLES 2019
Answer
1 mark for each correct term, in the correct place:
• Syntax
• High-level language
• Translator
• Machine code
• Assembly
• Low-level language
May/June 2019
www.dynamicpapers.com
Marks
6
Answer
Six from:
• SSL is a (security) protocol
• It encrypts any data that is sent
• It uses/sends digital certificates «
• « which is sent to the (buyer’s/user’s) browser // requested by (buyer’s/user’s) browser
• « that contains the gallery’s public key
• « that can be used to authenticate the gallery
• Once the certificate is authenticated, the transaction will begin
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Marks
6
0478/11
Question
8(b)
May/June 2019
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
1 mark for each correct tick.
6
Statement
True
(9)
False
(9)
9
Firewalls are only available as hardware devices
9
Firewalls allow a user to set rules for network traffic
Firewalls will automatically stop all malicious traffic
9
Firewalls only examine traffic entering a network
9
Firewalls encrypt all data that is transmitted around a network
9
Firewalls can be used to block access to certain websites
9
8(c)
Four from:
• A set of guidelines
• Rules/laws that govern the use of computers / by example
• Tell people how to behave when using computers // helps keep users safe when using computers // by example
• Art gallery could be subject to plagiarism / intellectual property theft
• Art gallery could copyright their work (to make it illegal to steal it)
© UCLES 2019
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
* 5 1 3 5 6 8 3 2 6 3 *
0478/12
COMPUTER SCIENCE
May/June 2019
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (KS/CB) 172695/2
© UCLES 2019
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1
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Input and output devices are often connected to a personal computer.
(a) Identify three input devices that can be connected to a personal computer.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
(b) Identify three output devices that can be connected to a personal computer.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
2
A finance company uses off-line storage to archive their accounts.
(a) Explain what is meant by off-line storage.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(b) The computers in the finance company use both primary and secondary storage.
(i)
Give one example of primary storage.
..................................................................................................................................... [1]
(ii)
Give two examples of secondary storage.
1 ........................................................................................................................................
2 ........................................................................................................................................
[2]
© UCLES 2019
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3
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Vanessa writes a paragraph as an answer to an examination question about the central processing
unit (CPU).
Use the list given to complete Vanessa’s answer by inserting the correct six missing terms.
Not all terms will be used.
•
•
•
•
•
•
•
•
•
Components
Data
Decoded
Executed
Fetched
Instructions
RAM
ROM
Secondary storage
The CPU processes ........................................................ and ........................................................ .
An instruction is ........................................................ from ........................................................
into the CPU where it is then ........................................................ . Once this has taken place the
instruction is then ........................................................ .
© UCLES 2019
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[6]
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(a) Marley wants to store a video he has created for his school project.
He considers using a DVD or a Blu-ray to store the video.
Explain two differences between a DVD and a Blu-ray.
1 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(b) (i)
Marley also needs to store ten 8-bit colour images in a file for his project.
Each image is 500 pixels wide and 300 pixels high.
Calculate the total file size in megabytes (MB) for all Marley’s images.
Show all your working.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
File size ....................................................... MB
© UCLES 2019
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[3]
5
(ii)
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Marley prints the images for his project using an inkjet printer.
Describe how the inkjet printer prints an image.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
5
A music company wants to send a new music file to many radio stations. It will send the music file
the day before the release date so that the radio stations can store the file ready for release.
The music company does not want the radio stations to be able to open the music file until 09:00
on the release date.
Identify two security measures and describe how each measure can be used to make sure the
music file cannot be opened until the release date.
Security measure 1 ..........................................................................................................................
Description .......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Security measure 2 ..........................................................................................................................
Description .......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
© UCLES 2019
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Priya creates a website to sell her old comic books and superhero figures.
(a) She uses HTML to create her website. The HTML she produces has both structure and
presentation.
Explain what is meant by HTML structure and presentation. Include an example of each.
Structure ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Presentation .............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
(b) Priya uses cookies in her website.
Five statements are given about cookies.
Tick (✓) to show if the statement is True or False.
Statement
True
(✓)
False
(✓)
Cookies can be used to store a customer’s credit card details
Cookies can be used to track the items a customer has viewed on a website
Cookies will corrupt the data on a customer’s computer
Cookies are downloaded onto a customer’s computer
Cookies can be deleted from a customer’s computer
[5]
© UCLES 2019
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(c) Priya stores her website on a webserver.
To transmit the website data to the webserver she uses parallel duplex data transmission.
Describe how data is transmitted using parallel duplex data transmission.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(d) Priya has a URL for her website.
State what is meant by a URL.
...................................................................................................................................................
............................................................................................................................................. [1]
(e) Priya is concerned about a denial of service attack (DoS) occurring on her webserver.
(i)
Explain what is meant by a denial of service attack.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(ii)
Give one security device that can be used to help prevent a denial of service attack.
..................................................................................................................................... [1]
© UCLES 2019
0478/12/M/J/19
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7
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(a) An office has an automated lighting system. When movement is detected in the office the
lights are switched on. If movement is not detected for a period of 2 minutes the lights are
switched off. The system uses a sensor and a microprocessor.
Describe how the automated lighting system uses a sensor and a microprocessor.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
(b) A microprocessor uses ROM.
Explain what is meant by ROM.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
© UCLES 2019
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8
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Consider the logic statement:
X = 1 if ((A is 1 NOR C is 1) AND (B is NOT 1 NOR C is 1)) OR (A is 1 AND B is 1)
(a) Draw a logic circuit to match the given logic statement. Each logic gate used must have a
maximum of two inputs. Do not attempt to simplify the logic statement.
A
X
B
C
[6]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2019
0478/12/M/J/19
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10
9
The contents of three binary registers have been transmitted from one computer to another. Even
parity has been used as an error detection method.
The outcome after transmission is:
Register A and Register C have been transmitted correctly.
Register B has been transmitted incorrectly.
Complete the Parity bit for each register to show the given outcome.
Parity bit
Register A
0
1
0
0
1
0
1
Register B
1
0
0
0
0
0
1
Register C
1
0
0
0
0
1
1
[3]
© UCLES 2019
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10 Remy has a mobile device that has a capacitive touch screen.
Describe how the capacitive touch screen registers Remy’s touch.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [4]
© UCLES 2019
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BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/12
Paper 1
May/June 2019
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2019 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and
some Cambridge O Level components.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
© UCLES 2019
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2019
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2019
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Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2019
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GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2019
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
May/June 2019
www.dynamicpapers.com
Marks
1(a)
Three from e.g.:
− Keyboard
− Mouse
− Microphone
− 2D scanner
− 3D scanner
− Touchscreen
− Webcam // digital camera
− Joystick
− Trackpad
− Sensor
− Interactive whiteboard
3
1(b)
Three from e.g.:
− Monitor // touchscreen
− Inkjet printer
− Laser printer
− 3D printer
− Speaker
− Headphones
− LED Projector
− DLP
− 2D cutter
− 3D cutter
− Actuator
3
© UCLES 2019
Page 4 of 12
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(a)
Answer
May/June 2019
www.dynamicpapers.com
Marks
Two from:
− It is non-volatile
− Can be easily disconnected from the computer
− It is not directly accessed by the CPU
− Suitable example e.g. CD, DVD, USB flash memory
2
2(b)(i)
One from:
− ROM
− RAM
1
2(b)(ii)
Two from:
− HDD
− SSD
− Flash memory
2
Question
3
© UCLES 2019
Answer
1 mark for each correct term, in the correct place:
− Data/instructions
− Instructions/data (must be the alternative to MP1)
− Fetched
− RAM
− Decoded
− Executed
Page 5 of 12
Marks
6
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)
4(b)(i)
Answer
© UCLES 2019
Marks
Two from e.g.:
− DVD uses red laser/light whereas blu-ray uses blue/violet laser/light
− DVD has a smaller (storage) capacity // Blu-ray has a larger (storage) capacity
− DVD has two layers (of polycarbonate) whereas Blu-ray disks have a single layer (of polycarbonate)
− DVD has a slower transfer rate (of approximately 10 mbps) // Blu-ray has a faster transfer rate
(of approximately 36 mbps)
2
2 marks for any two correct stages of working, 1 mark for correct answer.
− 500 * 300 * 10 // 150 000 *10
− * 8 then ÷ 8 (anywhere in the process)
− 1 500 000 ÷ 1024 ÷ 1024 // 1 500 000 ÷ 1 048 576
3
−
4(b)(ii)
May/June 2019
www.dynamicpapers.com
= 1.43 MB
Four from:
− Rollers are used to move the paper through the printer
− Nozzles spray/drop/jet ink onto the paper
− Ink jets/print head/nozzles are moved across the paper (to distribute the ink)
− Different colour inks are mixed to create required colours
− Technology could be piezoelectric
− Technology could be thermal bubble
−
−
−
−
Ink is heated
and expands/evaporates into a bubble
Bubble is pushed through the nozzle on to the paper
then the bubble collapses
−
−
−
Electrical current is applied to a crystal
which makes it vibrate
which forces a droplet of ink through the nozzle
Page 6 of 12
4
0478/12
Question
5
Answer
−
−
Password protection
Password is released on the release date
−
−
Encryption
Encryption key is released on the release date
Marks
4
Question
6(a)
May/June 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
Structure
− This is the layout of the web page
− e.g. placing an image alongside some text // example of tag, such as <div>
4
Presentation
− This is the formatting/style of the web page
− e.g. the colour that is applied to some text // example of tag, such as <font-color>
6(b)
1 mark per each correct row.
5
True
(9)
Statement
Cookies can be used to store a customer’s credit card details
9
Cookies can be used to track the items a customer has viewed
on a website
9
9
Cookies will corrupt the data on a customer’s computer
© UCLES 2019
Cookies are downloaded onto a customer’s computer
9
Cookies can be deleted from a customer’s computer
9
Page 7 of 12
False
(9)
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(c)
6(d)
Answer
−
−
−
−
Several/multiple bits are transmitted at a time/simultaneously
Several/multiple wires are used
Data is transmitted in both directions
at the same time/simultaneously
May/June 2019
www.dynamicpapers.com
Marks
4
One from:
− Uniform resource locator
− The website’s address
− User friendly version of the IP address
1
6(e)(i)
Four from:
− Designed to deny people access to a website
− A large number/numerous requests are sent (to a server)
−
all at the same time
− The server is unable to respond/struggles to respond to all the requests
− The server fails/times out as a result
4
6(e)(ii)
One from:
− Proxy server
− Firewall
1
© UCLES 2019
Page 8 of 12
0478/12
Question
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2019
www.dynamicpapers.com
Answer
Marks
7(a)
Six from:
− Motion sensor is used
− Sensor sends data/signal to microprocessor
− Data/Signal is converted from analogue data to digital data (using ADC)
− Value to compared to stored value(s) //
− If value is outside range/matches
−
microprocessor sends signal to switch lights on
−
actuator used to switch light on/off
−
timer is set for 2 minutes
− Every time movement is detected the timer is reset
− When timer reaches 0/120/times out microprocessor sends signal to switch lights off
− Process is continuous
6
7(b)
Three from:
− Read only memory
− Non-volatile memory // Contents of memory are retained when power is turned off//permanent storage
− Primary storage // directly accessed by the CPU
− Holds firmware/boot-up instructions/start-up instructions/BIOS
− Cannot be written to
3
© UCLES 2019
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0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8(a)
© UCLES 2019
Answer
1 mark per each correct logic gate, with correct input(s)
Page 10 of 12
May/June 2019
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Marks
6
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8(b)
© UCLES 2019
May/June 2019
www.dynamicpapers.com
Answer
Marks
4 marks for 8 correct outputs
3 marks for 6/7 correct outputs
2 marks for 4/5 correct outputs
1 mark for 2/3 correct outputs
4
A
B
C
Working space
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
1
1
1
1
1
Page 11 of 12
X
0478/12
Question
9
May/June 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
1 mark per each correct parity bit:
3
Parity bit
Question
10
© UCLES 2019
Register A
1
0
1
0
0
1
0
1
Register B
1
1
0
0
0
0
0
1
Register C
1
1
0
0
0
0
1
1
Answer
Four from:
− Electrical field/charge is spread across the screen
− Sensors are located around the screen // sensors are used to read the electric field
− When finger touches screen, the charge/ is transferred to the user
−
as it is affected by the conductivity of another object
− Coordinates of touch determined/calculated/measured
Page 12 of 12
Marks
4
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
* 0 8 5 8 6 2 0 4 7 3 *
0478/13
COMPUTER SCIENCE
May/June 2019
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 11 printed pages and 1 blank page.
DC (RW/CB) 172694/3
© UCLES 2019
[Turn over
2
1
www.dynamicpapers.com
Victoria is building a website for her cake design business.
(a) She uses the hexadecimal colour code #D2E3F5 as the background colour for her website.
The colour code is stored in two 12‑bit binary registers.
Show how the code would be stored in the registers.
D2E
3F5
[6]
(b) Victoria uses HTML to create her website.
State what is meant by HTML.
...................................................................................................................................................
............................................................................................................................................. [1]
(c) The HTML Victoria writes has both structure and presentation.
Five examples are given of structure and presentation.
Tick (✓) to show which example is Structure and which is Presentation.
Structure
(✓)
Example
Presentation
(✓)
The colour applied to a text heading on a web page
The font style applied to a paragraph of text on a web page
The placement of a paragraph of text on a web page
The size that an image is set to be displayed at on a web page
The placement of an image next to a paragraph of text on a web page
[5]
© UCLES 2019
0478/13/M/J/19
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(d) Customers will use a web browser to access Victoria’s website.
Victoria writes a paragraph of text to explain how the website will be displayed on a customer’s
computer.
Use the list given to complete Victoria’s paragraph by inserting the correct six missing terms.
Not all terms will be used.
•
•
•
•
•
•
•
•
•
•
browser
domain name
firewall
hexadecimal
HTML
https
MAC address
search engine
Uniform Resource Locator (URL)
web server
The user enters the website .................................................................. into the address bar.
The protocol that is used is .................................................................. . The URL contains
the .................................................................. for the website. This is used to look up the
IP address of the company. A DNS server stores an index of IP addresses.
The browser sends a request to the .................................................................. as this is
where the files for the website are stored. The files are sent back to the
.................................................................. as .................................................................. files.
This is interpreted by the browser and the web page is displayed.
© UCLES 2019
0478/13/M/J/19
[6]
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(e) When customers access Victoria’s website they will be given the message:
This website uses cookies. An explanation of their purpose can be found in our cookies policy.
(i)
Explain what is meant by cookies.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
Explain why Victoria would use cookies as part of her website.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
2
(a) A computer can have both a MAC address and an IP address.
Four statements are given about MAC addresses and IP addresses.
Tick (✓) to show whether each statement is True or False.
Statement
True
(✓)
False
(✓)
A MAC address is unique to a computer on a network
Once an IP address has been set it cannot be changed
A MAC address is made up of the computer’s serial number and
the IP address
If a computer does not have an IP address it cannot communicate
with another device using the Internet
[4]
© UCLES 2019
0478/13/M/J/19
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(b) A computer uses the Von Neumann model and the stored program concept.
(i)
Explain what is meant by the stored program concept.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
The Von Neumann model has several components that are used in the fetch‑execute
cycle.
One component is the Arithmetic Logic Unit (ALU).
Describe the role of the ALU.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(c) The computer has an operating system.
(i)
A signal causes the operating system to stop and assess what to do next.
Identify the name of this signal.
..................................................................................................................................... [1]
(ii)
State two functions of an operating system.
1 ........................................................................................................................................
2 ........................................................................................................................................
[2]
© UCLES 2019
0478/13/M/J/19
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3
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A finance company is concerned that its employees are being distracted by using gaming websites
at work.
(a) Explain how a firewall could help prevent this distraction.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) The finance company is also worried about the security of the data stored on its servers.
The company has decided to encrypt the data to improve the security.
Describe how the data are encrypted.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
© UCLES 2019
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7
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(c) The finance company realises that its computer systems have been hacked.
The company thinks that spyware was used to obtain a user’s password.
Explain how spyware could have been used to obtain the user’s password.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
© UCLES 2019
0478/13/M/J/19
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8
4
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Consider the given logic circuit:
A
X
B
C
(a) Redraw the logic circuit using only 4 logic gates. Each logic gate used must have a maximum
of two inputs.
A
X
B
C
[4]
© UCLES 2019
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9
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(b) Complete the truth table for the given logic circuit.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
(c) Describe the purpose of a logic gate in a logic circuit.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
© UCLES 2019
0478/13/M/J/19
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10
5
The three binary numbers in the registers given have been transmitted from one computer to
another.
One binary number has been transmitted incorrectly. This can be identified by the use of a Parity
bit.
Identify the binary number that has been transmitted incorrectly. Explain how you identified the
incorrect binary number.
Parity bit
Register A
1
0
1
1
1
0
0
1
Register B
1
1
1
0
0
1
1
1
Register C
1
0
0
1
1
0
1
1
The binary number that has been transmitted incorrectly is in Register ............................
Explanation ......................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [4]
© UCLES 2019
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11
6
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A museum has an information point.
Visitors to the museum can use the information point to plan their visit to the museum.
The information point allows visitors to access the information using a resistive touch screen.
Visitors can either listen to the information or read it on the screen. They can also select to output
a paper copy of the information they require.
(a) Describe how the resistive touch screen registers the visitor’s touch.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) The information point has a screen to allow visitors to read information.
Identify two other output devices that are present in the information point.
Output device 1 ........................................................................................................................
Output device 2 ........................................................................................................................
[2]
(c) The information point uses both primary and secondary storage.
Explain what is meant by primary and secondary storage.
Primary .....................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Secondary ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2019
0478/13/M/J/19
12
www.dynamicpapers.com
BLANK PAGE
Permission to reproduce items where third‑party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer‑related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019
0478/13/M/J/19
www.dynamicpapers.com
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
Paper 1 Theory
May/June 2019
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2019 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and
some Cambridge O Level components.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
© UCLES 2019
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2019
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond
the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2019
Page 2 of 12
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2019
www.dynamicpapers.com
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2019
Page 3 of 12
0478/13
May/June 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
Marks
1(a)
6
1
1
0
1
0
0
1
1
1 mark
1(b)
0
1
1
1
1
1
1
0
1 mark
1
0
1 mark
1
0
1
1 mark
One from:
−
−
1(c)
1
1 mark
1 mark
0
0
1
Hypertext Mark-up Language
A mark-up language used to create webpages
1 mark for each correct row:
5
Structure
(9)
Example
The colour applied to a text heading on a web page
9
The font style applied to a paragraph of text on a web page
9
9
The placement of a paragraph of text on a web page
9
The size that an image is set to be displayed at on a web page
The placement of an image next to a paragraph of text of a web page
© UCLES 2019
Presentation
(9)
Page 4 of 12
9
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(d)
1(e)(i)
1(e)(ii)
Answer
1 mark for each correct term, in the correct place:
−
−
−
−
−
−
URL
https
Domain name
Web server
Browser
HTML
−
−
Small packets of data
« that are stored by the web browser
© UCLES 2019
Marks
6
2
Four from:
−
−
−
−
−
May/June 2019
www.dynamicpapers.com
4
To store a customer’s password «
To store a customer’s credit card details «
« so they do not need to be re-entered in future
To track what the customer has viewed on the website «
« so she can send them adverts that match their preferences
Page 5 of 12
0478/13
Question
2(a)
Answer
4
True
(9)
Once an IP address has been set it cannot be changed
9
A MAC address is made up of the computer’s serial number and the IP
address
9
If a computer does not have an IP address it cannot communicate with
another device using the Internet
© UCLES 2019
False
(9)
9
A MAC address is unique to a computer on a network
2(b)(ii)
Marks
1 mark for each correct row:
Statement
2(b)(i)
May/June 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Two from:
9
2
−
−
−
Programs / instructions are stored in memory
Data is stored in memory
Instructions are fetched and executed one after another
−
−
−
−
Carries out calculations
Carries out logical operations
Holds temporary / interim values during calculations
« in a register called the accumulator (ACC)
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4
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(c)(i)
2(c)(ii)
Answer
−
© UCLES 2019
Marks
1
Interrupt
Two from:
−
−
−
−
−
−
−
−
−
−
−
−
−
May/June 2019
www.dynamicpapers.com
2
Provides an interface
Loads / opens / installs / closes software
Manages the hardware // manages peripherals // spooling
Manages the transfer of programs into and out of memory
Divides processing time // processor management
Manages file handling
Manages error handling // interrupt handling
Manages security software
Manages utility software
Manages user accounts
Multitasking
Multiprogramming // time slicing
Batch processing
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(a)
Answer
Four from:
−
−
−
−
−
3(b)
© UCLES 2019
The company could use the firewall to set criteria
Gaming websites can be listed as blocked websites // ports can be blocked
The firewall would examine any traffic leaving the network
If it detected traffic requesting a listed website, it will block access to it
Keeps a log of all attempts to access blocked websites
4
An encryption algorithm is used
« to scramble data
The original data is called the plain text
A key is used to encrypt the data
The key is applied to the plain text
Plain text is encrypted into cypher text
Six from:
−
−
−
−
−
−
−
Marks
4
Four from:
−
−
−
−
−
−
3(c)
May/June 2019
www.dynamicpapers.com
6
The user could have been sent an email with an attachment / link containing the spyware
The user could have clicked a link on an untrusted website
When the attachment / link was clicked the spyware was downloaded onto the user’s computer
The spyware recorded all the key logs from the user’s keyboard
The recorded key logs were sent back to the creator of the spyware
The key logs were analysed
A common pattern / word in the key logs could have allowed a password to be identified
Page 8 of 12
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)
© UCLES 2019
Answer
1 mark for each correct logic gate, with correct inputs:
May/June 2019
www.dynamicpapers.com
Marks
4
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(b)
4(c)
Answer
Marks
4 marks for 8 correct outputs
3 marks for 6/7 correct outputs
2 marks for 4/5 correct outputs
1 mark for 2/3 correct outputs
4
A
B
C
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
0
1
1
0
1
1
1
1
0
Working space
X
Two from:
−
−
−
© UCLES 2019
May/June 2019
www.dynamicpapers.com
2
To carry out a logical operation
To control the flow of electricity through a logic circuit
An input is given and the logic of the gate is applied to give an output // to alter the output from given inputs
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5
Answer
−
May/June 2019
www.dynamicpapers.com
Marks
4
B
Three from:
−
−
−
−
Added up the number of 1’s / 0’s in each register
With the parity bit, two registers have an odd number of 1’s / 0’s
One register has an even number of 1’s / 0’s
Odd parity must be the parity used
Question
6(a)
Answer
Four from:
−
−
−
−
−
6(b)
© UCLES 2019
4
Screen has two / multiple layers
Visitor presses on top layer
Top layer connects to bottom layer
« creating a circuit
Calculation is carried out on where layers are connected
Two from:
−
−
−
Marks
2
Speaker
Headphones
Printer
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(c)
May/June 2019
www.dynamicpapers.com
Answer
Four from (max. 2 marks per type):
4
Primary
− Memory that is directly accessed by the CPU
− An example is RAM / ROM
− RAM stores programs and data that are currently in use and ROM stores boot-up instructions
− RAM is volatile and ROM is non volatile
Secondary
− Storage that is not directly accessed by the CPU
− An example is HDD / SSD
− Stores data / files that can be accessed at a later stage
− Non volatile
© UCLES 2019
Marks
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
* 3 3 4 3 6 7 5 4 5 7 *
0478/11
COMPUTER SCIENCE
October/November 2019
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
Any businesses described in this paper are entirely fictitious.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
DC (SC/SG) 163095/2
© UCLES 2019
[Turn over
2
1
www.dynamicpapers.com
Andrew wants to produce advertising material for his company.
(a) Andrew can use an Inkjet printer or a Laser printer.
Draw lines to connect each printer to a correct statement. More than one line may be used to
connect to each printer or statement.
Printer
Statement
Can print in colour
Inkjet printer
Uses a charged drum to
create the printed item
Uses powdered toner
Laser printer
Creates output line by line
using a print head
[2]
(b) Andrew wants to print a single page A4 leaflet. He wants to print 10 000 copies.
State whether he should use an inkjet or a laser printer.
............................................................................................................................................. [1]
(c) Andrew wants to produce small 3D models of the company logo.
Explain how a 3D cutter could be used to produce the models.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
© UCLES 2019
0478/11/O/N/19
3
2
www.dynamicpapers.com
An electronic guessing game compares denary integer values input by a user with pre-stored
values. The pre-stored values are held in 10-bit binary format.
(a) Convert the binary values in the table to denary.
Binary
Denary
0001001110
0110110111
1000000001
[3]
(b) When planning the game, the designer decided to use hexadecimal notation to represent the
binary values.
Explain why the designer used hexadecimal notation.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(c) State the hexadecimal equivalent of the binary value 1010110101
............................................................................................................................................. [3]
3
A company has several offices. It uses the Internet to transfer data between offices. The company
also makes payments to staff and suppliers using online banking.
The company are concerned about spyware and other security aspects of using the Internet.
(a) Explain what is meant by spyware and how it is used to obtain data.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
© UCLES 2019
0478/11/O/N/19
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4
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(b) The company uses a web page to log on to the online bank.
Identify one method that could be used by the online bank to reduce the impact of spyware
when logging on.
State how the method prevents the use of spyware.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(c) The company has installed a firewall as part of its data security.
Describe how a firewall can help protect against unauthorised access to data.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(d) State two other methods the company could use to help prevent unauthorised access to
data.
Method 1 ...................................................................................................................................
Method 2 ...................................................................................................................................
[2]
© UCLES 2019
0478/11/O/N/19
5
4
www.dynamicpapers.com
A zoo has an information point.
•
•
•
Visitors use a menu to select information about animals.
The menu includes 500 different animals.
The information is provided only using high definition video with an audio track.
(a) State one input device that could be used for the information point.
............................................................................................................................................. [1]
(b) The output is shown on a monitor.
State one other output device that could be used for the information point.
............................................................................................................................................. [1]
(c) The video files are stored at the information point.
State one secondary storage device that could be used.
............................................................................................................................................. [1]
(d) The zoo decides to introduce Quick Response codes in different places in the zoo. These
provide further information about the animals.
Describe how customers obtain the information from the Quick Response codes.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
© UCLES 2019
0478/11/O/N/19
[Turn over
www.dynamicpapers.com
6
5
Sonia shares files with her friends. The method of data transmission she uses is half-duplex serial
transmission.
(a) Describe how data is transmitted using half-duplex serial data transmission.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) The system uses parity bits to check for errors during data transmission.
The outcome of four bytes after transmission is:
Byte 1
Byte 2
Byte 3
Byte 4
00110011
01010100
10110100
01110111
One of the bytes has been transmitted incorrectly.
Identify the byte that was transmitted incorrectly.
Byte ...........................................................
Explain how you identified the byte that was transmitted incorrectly.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[4]
© UCLES 2019
0478/11/O/N/19
7
6
www.dynamicpapers.com
Ishan is a member of a software community that develops computer games. He has programmed
a new feature for one of the community’s existing games.
(a) Ishan compiles the program before he issues it to the community.
(i)
Explain one benefit of Ishan compiling the program.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
Explain one drawback of Ishan compiling the program.
...........................................................................................................................................
..................................................................................................................................... [1]
(b) Ishan shares the program with community members over the Internet, using Secure Socket
Layer (SSL).
(i)
Explain how Ishan will know he is on a secure website.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
Describe how an SSL connection is established.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [5]
© UCLES 2019
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(c) The community publishes completed games on the Internet as freeware.
Describe what is meant by freeware.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(d) The program files for the games are compressed before they are published on the Internet.
(i)
Describe one benefit of compressing the program files.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
State whether lossy or lossless compression should be used.
..................................................................................................................................... [1]
© UCLES 2019
0478/11/O/N/19
9
7
www.dynamicpapers.com
A factory manufactures plastic pipes. It uses logic circuits to control the manufacturing process.
(a) Consider the logic gate:
Input A
Input B
Output
Complete the truth table for this logic gate.
Input A
Input B
0
0
0
1
1
0
1
1
Output
[1]
(b) Consider the truth table:
Input A
Input B
Output
0
0
0
0
1
1
1
0
1
1
1
0
State the single logic gate that produces the given output.
............................................................................................................................................. [1]
© UCLES 2019
0478/11/O/N/19
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10
(c) Plastic pipes of various sizes are manufactured by heating the plastic and using pressure.
The manufacturing system uses sensors to measure the pressure (P), temperature (T) and
speed (S) of production.
The inputs to the manufacturing system are:
Input
P
T
S
Binary value
Condition
1
pressure is > 5 bar
0
pressure is <= 5 bar
1
temperature is > 200 degrees Celsius
0
temperature is <= 200 degrees Celsius
1
speed is > 1 metre per second
0
speed is <= 1 metre per second
The system will sound an alarm (X) when certain conditions are detected.
The alarm will sound when:
Temperature is > 200 degrees Celsius and the pressure is <= 5 bar
or
Speed is > 1 metre per second and Temperature is <= 200 degrees Celsius
Draw a logic circuit to represent the above alarm system.
Logic gates used must have a maximum of two inputs.
P
T
X
S
[5]
© UCLES 2019
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11
www.dynamicpapers.com
(d) Give two benefits of using sensors to monitor the manufacture of plastic pipes.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
[2]
8
Explain how an instruction is fetched in a Von Neumann model computer.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [6]
9
HTML can be used to create the structure and the presentation of web pages.
(a) Describe what is meant by HTML structure.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
© UCLES 2019
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(b) Gloria writes a paragraph as an answer to an examination question about accessing a
website.
Use the list given to complete Gloria’s answer by inserting the correct four missing terms. Not
all terms will be used.
•
•
•
•
•
•
•
•
browser
cookies
Hypertext Markup Language (HTML)
hypertext transfer protocol (http)
hypertext transfer protocol secure (https)
Internet Protocol address (IP address)
Media Access Control address (MAC address)
web server
The user enters the URL of the website. The ............................................................... uses
the DNS server to look up the ............................................................... of the website.
The browser sends a request to the ............................................................... to obtain the
website files. The website files are sent as ............................................................... that is
interpreted by the browser.
[4]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019
0478/11/O/N/19
www.dynamicpapers.com
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/11
Paper 1
October/November 2019
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2019 series for most
Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level
components.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
© UCLES 2019
[Turn over
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
October/November 2019
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond
the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2019
Page 2 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
October/November 2019
www.dynamicpapers.com
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range
may be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2019
Page 3 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
1(a)
Printer
Statement
October/November 2019
www.dynamicpapers.com
Marks
2
Can print in colour
Inkjet printer
Uses a charged drum to
create the printed item
Laser printer
Uses powdered toner
Creates output line by line
using a print head
One mark for correct lines from inkjet
One mark for correct lines from laser
1(b)
•
1(c)
Two from:
• Design is created on the computer / software / CAD
• Material is loaded to cutter
• Different types of material can be used
• Uses lasers to cut material «
• « that use infra-red
• « that produces extreme heat
• « that is focussed using a special lens
• Can work on both the x,y and z axis
© UCLES 2019
1
Laser
Page 4 of 12
2
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(a)
Answer
One mark for each correct denary value
Binary
October/November 2019
www.dynamicpapers.com
Marks
3
Denary
0001001110
78
0110110111
439
1000000001
513
2(b)
Two from:
• Uses fewer characters // shorter
• Easier to read / write / understand
• Less likely to make mistakes // less error prone
• Easier to debug
2
2(c)
One mark for each correct hexadecimal value in correct order
2
B
5
3
© UCLES 2019
Page 5 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
October/November 2019
www.dynamicpapers.com
Answer
Marks
3(a)
Three from:
• Malicious software // type of malware
• Tracks / records keypresses // keylogger
• Sends data to third party
• Collected data is analysed to obtain data
3
3(b)
One mark for identified method, one mark for how it prevents spyware:
2
Drop-down boxes // onscreen / virtual keyboard
• Means key logger cannot collect data
Only requires part of the password
• Hacker doesn’t get the full password
Two-step verification // Two-factor authentication
• Extra data is sent to device making it more difficult for hacker to obtain it
• Data has to be entered into the same system // if attempted from a remote location, it will not be accepted
Use a biometric device
• The person's biological data (e.g. their fingerprint) is also required
3(c)
Four from:
• Monitors traffic coming into and out of the computer system
• Checks that the traffic meets any criteria / rules set
• Blocks any traffic that does not meet the criteria / rules set
• Allows a set blacklist / whitelist // can block certain IP addresses
• Can close certain ports
4
3(d)
Two from:
• Passwords // biometrics
• Levels of access
• Proxy servers
• Physical security methods – e.g. PC’s in locked rooms, etc.
2
© UCLES 2019
Page 6 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2019
www.dynamicpapers.com
Marks
4(a)
One from:
• Touch screen
• Keyboard
• Microphone
• Mouse
1
4(b)
One from:
• Headphones
• Speakers
• Printer
• Light / LED
1
4(c)
One from:
• HDD
• SSD
• USB drive
1
4(d)
Four from:
• QR code is scanned using a camera on a mobile device «
• « and read / decoded using an application / software
• Illuminator shone on code
• Squares reflect light differently
• Corners of code are used for orientation
• Opens document with information // Directs to website with information
• QR code can be saved for future reference
4
© UCLES 2019
Page 7 of 12
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
5(a)
•
•
•
•
5(b)
One mark for correct byte
(Byte) 2 // 01010100
Marks
4
Data is sent down a single wire «
« one bit at a time
Data is sent in both directions «
« but only one direction at a time
4
Three from:
• Added up / counted the 1s / 0s
• Even parity used // 3 bytes are even
• Byte 2 uses odd parity // 1 byte is odd
© UCLES 2019
October/November 2019
www.dynamicpapers.com
Page 8 of 12
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2019
www.dynamicpapers.com
Marks
6(a)(i)
One from:
• Code will run without the need of an interpreter
• (Object) Code is platform independent
• Source code not available / cannot be modified
1
6(a)(ii)
One from:
• Source code not available / cannot be modified
• Comments, etc. not visible
• Future changes will require code to be recompiled
1
6(b)(i)
One from:
• Protocol is HTTPS
• Padlock icon is locked
• Can view website certificate
1
6(b)(ii)
Five from:
• Browser / client sends request to webserver to request identification
• Web server sends its digital / security certificate
• Browser authenticates certificate «
• « if authentic connection, is established
• Any data sent is encrypted «
• « using public and private keys
5
Four from:
• A type of software licence
• Free of charge
• Normally distributed without the source code
• Can legally share / copy
• Cannot legally modify code
• Cannot resell
4
6(c)
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PUBLISHED
Question
Answer
October/November 2019
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Marks
6(d)(i)
Two from:
• File size is reduced «
• « so it uses less storage space
• « so faster transmission
• « so quicker to download
2
6(d)(ii)
•
1
© UCLES 2019
Lossless
Page 10 of 12
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
7(a)
Input A
Input B
Output
0
0
0
0
1
1
1
0
1
1
1
1
October/November 2019
www.dynamicpapers.com
Marks
1
7(b)
•
7(c)
One mark for each correct logic gate with correct inputs
5
7(d)
Two from:
• Can work continuously
• Avoids human error
• It could be a dangerous environment and will avoid human risk
• Detect errors instantly
• Maintain consistent and correct conditions
2
© UCLES 2019
1
Exclusive OR / XOR / EOR
Page 11 of 12
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8
Answer
October/November 2019
www.dynamicpapers.com
Marks
Six from:
• PC holds address of the instruction
• The address held in PC is sent to MAR «
• « using address bus
• MAR goes to location in memory where instruction is stored
• Instruction sent to MDR «
• « using data bus
• Instruction sent to CIR
• Control unit sends signals to manage the process «
• « using the control bus
6
9(a)
Two from:
• Layout of the webpage
• e.g. where a paragraph is placed
• Defined using tags
2
9(b)
One mark for each correct term in the correct order:
• browser
• IP address
• web server
• HTML
4
© UCLES 2019
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Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
* 2 0 5 9 2 6 7 9 2 0 *
0478/13
COMPUTER SCIENCE
October/November 2019
Paper 1 Theory
1 hour 45 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
No calculators allowed.
READ THESE INSTRUCTIONS FIRST
Write your centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 12 printed pages.
DC (PQ/TP) 173648/2
© UCLES 2019
[Turn over
2
1
www.dynamicpapers.com
A library has a system that allows customers to check out the books that they want to borrow.
Each book has a barcode that can be used to identify the book.
(a) (i)
Identify two input devices that may be used in the library’s system.
Input device 1 ....................................................................................................................
Input device 2 ....................................................................................................................
[2]
(ii)
Identify two storage devices that may be used in the library’s system.
Storage device 1 ...............................................................................................................
Storage device 2 ...............................................................................................................
[2]
(iii)
Identify two output devices that may be used in the library’s system.
Output device 1 .................................................................................................................
Output device 2 .................................................................................................................
[2]
(b) The data stored by the library is archived at the end of each day. The archive is held on a
server in the library office.
The data is encrypted with an 8-bit key. As some of the data is confidential, the library wants
to make the encryption more secure.
(i)
State how the library could make the encryption more secure.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
The term used to describe data before it is encrypted is plain text.
State the term used to describe encrypted data.
..................................................................................................................................... [1]
© UCLES 2019
0478/13/O/N/19
3
(iii)
www.dynamicpapers.com
The library’s archive system uses an error detection and correction system that combines
a parity check with an automatic repeat request (ARQ).
Describe how this system uses the parity check and ARQ.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [6]
(c) The library has a website that customers can use to search for a book.
(i)
The website has a background colour with the hexadecimal colour code #F92A10
The colour code is stored in two 12-bit binary registers.
Show how the colour code would be stored in the registers.
F92
A10
[6]
© UCLES 2019
0478/13/O/N/19
[Turn over
4
(ii)
www.dynamicpapers.com
Videos on the library website show customers which books the library will soon have
in stock.
The library wants the file size of a video to be as small as possible.
Identify and describe a method the library could use to reduce the file size of a video as
much as possible.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(d) The library often holds events that introduce new authors.
At the events, the library has a Liquid Crystal Display (LCD) screen that displays data,
including an image and information about the author.
Describe how an LCD screen operates to display this data.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [5]
© UCLES 2019
0478/13/O/N/19
5
2
www.dynamicpapers.com
A programmer uses a high-level language to write a computer program.
(a) Four statements are given about high-level programming languages.
Tick (3) to show if each statement is True or False.
True
(3)
Statement
False
(3)
High-level languages need to be translated into machine code to run on a
computer
High-level languages are written using mnemonic codes
High-level languages are specific to the computer’s hardware
High-level languages are portable languages
[4]
(b) Tick (3) to show which of the following is an example of a high-level language program.
Example program
Tick
(3)
1011100000110000
0000011011100010
INP
STA ONE
INP
STA TWO
ADD ONE
a = input()
b = input()
if a == b:
print("Correct")
else:
print("Incorrect")
[1]
© UCLES 2019
0478/13/O/N/19
[Turn over
6
3
www.dynamicpapers.com
Blair writes a paragraph about data transmission in her Computer Science examination.
Use the list given to complete Blair’s paragraph by inserting the correct five missing terms. Not all
terms will be used. Terms can be used more than once.
•
•
•
•
•
duplex
half-duplex
parallel
serial
simplex
....................................................................... data transmission is when data is transmitted a
single bit at a time. ....................................................................... data transmission is when
multiple bits of data are sent all at once. If a user wants to transmit data over a long distance, with
the highest chance of accuracy, ....................................................................... data transmission
should be used. If data needs to be transmitted in one direction only, for example from a computer
to a printer, ....................................................................... data transmission should be used. If a
user has a large amount of data to transmit and this needs to be done as quickly as possible
....................................................................... data transmission should be used.
© UCLES 2019
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[5]
7
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Question 4 starts on page 8.
© UCLES 2019
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8
4
www.dynamicpapers.com
A factory that manufactures cleaning products has a system that monitors conditions throughout
the manufacturing process.
The inputs to the system are:
Input
A
T
P
Binary value
Condition
1
pH > 7
0
pH < = 7
1
Temperature < 35 °C
0
Temperature > = 35 °C
1
Pressure > = 80 %
0
Pressure < 80 %
(a) The system will sound an alarm (X) when certain conditions are detected.
The alarm will sound when:
•
The pressure > = 80 % and the temperature > = 35 °C
or
•
The temperature < 35 °C and the pH > 7
Draw a logic circuit to represent the alarm system in the factory. Each logic gate must have a
maximum of two inputs.
A
T
X
P
[4]
© UCLES 2019
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9
www.dynamicpapers.com
(b) Complete the truth table for the given logic problem.
A
T
P
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
(c) A sensor and a microprocessor are used to monitor the pH of the cleaning products. The
system records each reading that is taken. If the reading is greater than 7 a warning message
is displayed on a monitor.
Explain how the sensor and microprocessor are used in the system.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
© UCLES 2019
0478/13/O/N/19
[Turn over
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10
5
The contents of three binary registers have been transmitted from one computer to another. Odd
parity has been used as an error detection method.
The outcome after transmission is:
•
Register A and Register B have been transmitted correctly.
•
Register C has been transmitted incorrectly.
Write the appropriate Parity bit for each register to show the given outcome.
Parity
bit
Register A
0
1
0
0
0
1
1
Register B
0
0
0
0
1
1
1
Register C
0
0
0
0
0
1
1
[3]
6
Jesse is taking his Computer Science examination. He answers five questions about ethics.
(a) For the first question, he writes the answer:
“This type of software can be copied and shared without the permission of the owner.”
State what Jesse is describing.
............................................................................................................................................. [1]
(b) For the second question, he writes the answer:
“With this type of software, the owner still retains the copyright for the software, but he gives
away copies of it for free.”
State what Jesse is describing.
............................................................................................................................................. [1]
(c) For the third question, he writes the answer:
“This type of software is often a trial version of the full software. To use the full version the
user normally needs to pay a fee.”
State what Jesse is describing.
............................................................................................................................................. [1]
© UCLES 2019
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11
www.dynamicpapers.com
(d) For the fourth question, he writes the answer:
“This is when a person copies another person’s computer program and tries to claim it as his
own.”
State what Jesse is describing.
............................................................................................................................................. [1]
(e) For the fifth question, he writes the answer:
“This is the legal protection that a person can obtain, to provide protection against his work
being stolen.”
State what Jesse is describing.
............................................................................................................................................. [1]
7
The Von Neumann model for a computer system has several components that are used in the
fetch-execute cycle.
(a) One component is main memory.
(i)
Describe what is meant by main memory and how it is used in the Von Neumann model
for a computer system.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(ii)
State two other components in the Von Neumann model for a computer system.
1 ........................................................................................................................................
2 ........................................................................................................................................
[2]
© UCLES 2019
0478/13/O/N/19
[Turn over
12
www.dynamicpapers.com
(b) Computer systems often use interrupts.
Five statements are given about interrupts.
Tick (3) to show if each statement is True or False.
Statement
True
(3)
False
(3)
Interrupts can be hardware based or software based
Interrupts are handled by the operating system
Interrupts allow a computer to multitask
Interrupts work out which program to give priority to
Interrupts are vital to a computer and it cannot function without them
[5]
8
A company discovers malware on its network.
Explain two ways that the malware could have been introduced to the company’s network.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [4]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019
0478/13/O/N/19
www.dynamicpapers.com
Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
COMPUTER SCIENCE
0478/13
Paper 1
October/November 2019
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2019 series for most
Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level
components.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 14 printed pages.
© UCLES 2019
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
October/November 2019
www.dynamicpapers.com
Generic Marking Principles
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific
content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking
principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope
of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question
as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.
© UCLES 2019
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PUBLISHED
October/November 2019
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GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be
limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade
descriptors in mind.
© UCLES 2019
Page 3 of 14
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2019
www.dynamicpapers.com
Marks
1(a)(i)
Two from:
• 2D scanner
• Touchscreen
• Keypad/keyboard
• Card reader
• Mouse
• Digital camera
2
1(a)(ii)
Two from:
• HDD
• SSD
• USB flash memory drive
• SD card
• Any optical
2
1(a)(iii)
Two from:
• Monitor/Touch screen
• Speaker
• Printer
• LED // Light
2
1(b)(i)
•
Increase the length of the key // make key 12-bit, etc.
1
1(b)(ii)
•
Cypher text
1
© UCLES 2019
Page 4 of 14
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(b)(iii)
1(c)(i)
Answer
If parity is correct no error is found
An acknowledgement is sent that data is received correctly
The next packet of data is transmitted
•
•
•
If incorrect parity is found an error has occurred
A signal is sent back to request the data is resent
The data is resent until data is received correctly/timeout occurs
1
1
1
1
1
1 mark
1
0
0
0
1
0
1
0
0
0
1 mark
0
1
6
0
1 mark
1 mark
1 mark
© UCLES 2019
Marks
Six from:
• The system could use odd or even parity
• A parity bit is added
• The data is checked to see if it has incorrect/correct parity // by example
•
•
•
0
1
0
0
0
1 mark
Page 5 of 14
October/November 2019
www.dynamicpapers.com
0
6
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(c)(ii)
October/November 2019
www.dynamicpapers.com
Answer
One mark for identification:
• Compression
Marks
4
Three from e.g.:
• Best compression would be lossy
• Use compression algorithm
• This would remove all the unnecessary data from the file // removes detail/sound that the human eye/ear may not see/hear
• Reduce colour palette «
• « so each pixel requires fewer bits
• Reduce resolution
• Only store what changes between frames // temporal redundancy
1(d)
© UCLES 2019
Five from:
• The display is made up of pixels «
• « that are arranged together as a matrix
• Each pixel has three filters, red, blue and green
• Shades of colour are achieved by mixing red, blue and green
• The screen is backlit
• Light is shone through the liquid crystals
• The liquid crystals can be made to turn solid or transparent/on or off «
• « by changing the shape of the crystal
Page 6 of 14
5
0478/13
Question
2(a)
Answer
Marks
One mark for each correct row
4
True
(9)
Statement
High-level languages need to be translated into machine code to run on a
computer
False
(9)
9
High-level languages are written using mnemonic codes
9
High-level languages are specific to the computer’s hardware
9
9
High-level languages are portable languages
© UCLES 2019
October/November 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Page 7 of 14
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(b)
Answer
One mark for the correct tick
Example program
October/November 2019
www.dynamicpapers.com
Marks
1
Tick
(9)
1011100000110000
0000011011100010
INP
STA ONE
INP
STA TWO
ADD ONE
a = input()
b = input()
if a == b:
print("Correct")
else:
print("Incorrect")
9
Question
3
© UCLES 2019
Answer
One mark for each correct term in the correct order
• Serial
• Parallel
• Serial
• Simplex
• Parallel
Marks
5
Page 8 of 14
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)
© UCLES 2019
Answer
One mark for each correct logic gate with correct input(s)
October/November 2019
www.dynamicpapers.com
Marks
4
Page 9 of 14
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(b)
4(c)
© UCLES 2019
Answer
October/November 2019
www.dynamicpapers.com
Marks
Four mark for 8 correct outputs
Three marks for 6 or 7 correct outputs
Two mark for 4 or 5 correct outputs
One mark for 2 or 3 correct outputs
4
A
T
P
Working space
X
0
0
0
0
0
0
1
1
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
1
Six from:
• Sensor sends a signal/reading/data to the microprocessor
• Signal/reading/data is analogue and is converted to digital using ADC
• Reading/data is stored in the system
• Microprocessor compares data/reading to the pre-set value of 7
• If value is greater than 7 «
• « a signal/data is sent by the microprocessor to display a warning message on a monitor
• The process is continuous
Page 10 of 14
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Question
5
October/November 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
One mark for each correct parity bit
3
Parity
bit
Register A
0
0
1
0
0
0
1
1
Register B
0
0
0
0
0
1
1
1
Register C
0
0
0
0
0
0
1
1
Question
Answer
Marks
6(a)
•
Free software
1
6(b)
•
Freeware
1
6(c)
•
Shareware
1
6(d)
•
Plagiarism // Intellectual property theft
1
6(e)
•
Copyright
1
© UCLES 2019
Page 11 of 14
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2019
www.dynamicpapers.com
Marks
7(a)(i)
Three from:
• RAM
• Primary memory
• Volatile memory
• Holds currently in use data/instructions
• Directly accessed by the CPU
3
7(a)(ii)
Two from:
• Arithmetic and logic unit (ALU)
• Memory address register (MAR)
• Memory data register (MDR) // Memory buffer register (MBR)
• Accumulator (ACC)
• Immediate Access Store (IAS)
• Control Unit (CU)
• Program counter (PC)
• Current instruction register (CIR)
• Address bus
• Data bus
• Control bus
• Input device
• Output device
• Secondary storage device
2
© UCLES 2019
Page 12 of 14
0478/13
Question
7(b)
Answer
Marks
One mark for each correct row
5
True
(9)
Statement
Interrupts can be hardware based or software based
9
Interrupts are handled by the operating system
9
Interrupts allow a computer to multitask
9
False
(9)
9
Interrupts work out which program to give priority to
Interrupts are vital to a computer and it cannot function without them
© UCLES 2019
October/November 2019
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Page 13 of 14
9
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
8
© UCLES 2019
Answer
Four from:
• A hacker could have hacked the network «
• « and downloaded the malware onto the network
October/November 2019
www.dynamicpapers.com
Marks
4
•
•
Clicking a link/attachment/downloaded a file from an email/on a webpage «
« the malware could have been embedded into the link/attachment/file
•
•
Opening an infected software package «
« this would trigger the malware to download onto the network
•
•
Inserting an infected portable storage device «
« when the drive is accessed the malware is downloaded to the network
•
•
Firewall has been turned off «
« so malware would not be detected/checked for when entering network
•
•
Anti-malware has been turned off «
« so malware is not detected/checked for when files are downloaded
Page 14 of 14
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Cambridge IGCSE®
*0123456789*
0478/01
COMPUTER SCIENCE
Paper 1 Theory
For examination from 2020
SPECIMEN PAPER
1 hour 45 minutes
Candidates answer on the question paper.
No additional materials are required.
READ THESE INSTRUCTIONS FIRST
Write your centre number, candidate number and name in the spaces at the top of this page.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams, graphs or rough working.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Calculators must not be used in this paper.
Answer all questions.
No marks will be awarded for using brand names of software packages or hardware.
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
The maximum number of marks is 75.
This document consists of 14 printed pages.
© UCLES 2017
[Turn over
2
1
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A company selling CDs uses a unique 6-digit identification number for each CD title. The rightmost digit (position 1) is a check digit.
For example,
digit position
identification number
6 5 4 3 2 1
3 0 6 1 4 9
check digit
The validity of the number and check digit is calculated as follows:
•
•
•
•
multiply each digit by its digit position
add up the results of the multiplications
divide the answer by 11
if the remainder is 0, the identification number and check digit are valid.
(a) Show whether the following identification numbers are valid or not. You must show how you
arrived at your answer.
Identification number 1: 4 2 1 9 2 3
working:
valid or not valid?
Identification number 2: 8 2 0 1 5 6
working:
valid or not valid?
© UCLES 2017
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(b) Find the check digit for this identification number.
5 0 2 4 1 __
working:
check digit:
[2]
(c) Describe, with examples, two different types of data entry errors that a check digit would
detect.
1
2
[2]
2
Kamil is setting up a new computer system to record television programmes. He wants to be able
to record, view and then erase programmes that he does not want to keep. He has chosen to use
DVD-RAM as an optical storage medium.
Explain to Kamil why it is better to use DVD-RAM rather than DVD+RW or DVD-RW.
1
2
[2]
© UCLES 2017
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4
3
An alarm, Y, sends a signal (Y = 1) when certain fault conditions in a chemical process are
detected. The inputs are:
Input
Binary value
Condition
1
acidity > 5
0
acidity <= 5
1
temperature >= 120°C
0
temperature < 120°C
1
stirrer bar ON
0
stirrer bar OFF
A
T
S
The alarm, Y, returns a value of 1 if:
either
temperature >= 120°C AND stirrer bar is OFF
or
acidity > 5 AND temperature < 120°C
(a) Draw the logic circuit for the above system using these logic gates.
NOT
AND
OR
A
Y
T
S
[5]
© UCLES 2017
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5
(b) Complete the truth table for this alarm system.
A
T
S
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Y
[4]
© UCLES 2017
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4
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A digital alarm clock is controlled by a microprocessor. It uses the 24-hour clock system (i.e. 6 pm
is 18:00).
Each digit in a typical display is represented by a 4-digit binary code.
For example:
0
0
0
0
1st digit (0)
1
0
0
0
2nd digit (8)
0
0
1
1
3rd digit (3)
0
1
0
1
4th digit (5)
is represented by:
(clock display)
(a) What time is shown on the clock display if the 4-digit binary codes are:
0
0
0
1
0
1
1
0
0
1
0
0
1
0
0
1
(clock display)
[2]
(b) What would be stored in the 4-digit binary codes if the clock display time was:
1st digit
2nd digit
3rd digit
4th digit
[4]
© UCLES 2017
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(c) The clock alarm has been set at 08:00.
Describe the actions of the microprocessor which enable the alarm to sound at 08:00.
[2]
5
Bytes of data transferred using a serial cable are checked for errors at the receiving end using an
even parity check.
Can these bytes of data pass the even parity check?
(a) 01010101
[1]
(b) 11001000
[1]
(c) How can any errors be corrected?
[2]
© UCLES 2017
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6
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The conditions in a fish tank are being controlled using sensors and a microprocessor. To keep
the fish healthy, the temperature must be at 25°C and the oxygen content needs to be 20 ppm
(parts per million). The tank contains a heater and an oxygen inlet controlled by a valve.
heater
oxygen supply
sensor A
sensor B
microprocessor
(a) Name the two sensors used in this application.
Sensor A
Sensor B
[2]
(b) Describe how the sensors and the microprocessor are used to maintain the correct
conditions in the fish tank.
[4]
(c) What safeguards are needed to stop the fish tank temperature rising too high?
[1]
© UCLES 2017
0478/01/SP/20
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7
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Ahmed uses the Internet for some time and is puzzled by the terminology.
(a) Draw a line to match each description to the appropriate technical term.
authoring language used to
create documents to be viewed
on the World Wide Web
Browser
computer that responds to
requests to provide information
and services over the Internet
HTML
defines how messages are
transmitted and formatted
over the Internet
MAC address
numerical ID for each device
on the Internet
Internet Server
software that enables users
to access/view documents and
other resources on the Internet
IP address
unique ID for a network
interface card
http
[5]
(b) Ahmed sees the message “Set your browser to accept cookies”.
Explain why some websites make this request.
[2]
© UCLES 2017
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8
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Computer memories are measured in terms of the number of bytes.
(a) (i) What is meant by the term byte?
[1]
(ii) The number of bytes in a Gigabyte can be written as 2x
What is the value of x?
[1]
(b) Flash memories and CD-RWs are used as backing media for computers.
Give two differences between these two media.
1
2
[2]
9
Andrew sends a large document to a printer.
(a) State the name for the area of memory used to store temporarily the data being sent to the
printer.
[1]
(b) The printer runs out of paper during the printing job. A signal is sent back to the computer to
stop temporarily its current task.
Name this type of signal.
[1]
© UCLES 2017
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10 In a simple symmetric encryption system, each letter of the alphabet is substituted with another.
The plain text message:
The quick brown fox jumps over the lazy dog.
becomes the cypher text message:
Zag towvs jumpy dmh coilr mngu zag bfke qmx.
(a) (i) Decode this cypher text message.
Agbbm Pmubq
[2]
(ii) Convert these words to cypher text.
Computer Science
[2]
(b) Both the person who sends the message and the person who receives it need to know
what the substitution key is, and they need to keep this secret. A copy of the
substitution key has been sent using SSL transmission.
(i) What is meant by SSL?
[1]
(ii) How does SSL keep the copy of the key secret during transmission?
[1]
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11 Five security or data loss issues are shown on the left-hand side.
Five possible methods of data recovery or protection are shown on the right.
Draw a line to match each definition/description of Issues to the most appropriate Methods of
Data Recovery.
Issues
Methods of Data Recovery
data loss caused by hard disk
head crash
anti-spyware software
hacking into files and changing
or deleting data
anti-virus software
introduction of software that
self-replicates and can cause
data loss
back-up files
reading of illegally accessed
documents
encryption
software that logs/records all
key presses on your computer
without you knowing
passwords and a firewall
[4]
© UCLES 2017
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12 Look at these two pieces of code:
A:
CLC
LDX
loop: LDA
ADC
STA
INX
CPX
BNE
#0
A,X
B,X
C,X
B: FOR Loop
INPUT
Sum =
PRINT
NEXT
= 1 TO 4
Number1, Number2
Number1 + Number2
Sum
#16
loop
(a) Which of these pieces of code is written in a high-level language?
[1]
(b) Give one benefit of writing code in a high-level language.
[1]
(c) Give one benefit of writing code in a low-level language.
[1]
(d) High-level languages can be compiled or interpreted.
Give two differences between a compiler and an interpreter.
1
2
[2]
© UCLES 2017
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14
13 When a key is pressed on the keyboard, the computer stores the ASCII representation of the
character typed into main memory.
The ASCII representation for A is 65 (denary), for B is 66 (denary), etc.
There are two letters stored in the following memory locations:
Location 1
A
Location 2
C
(a) (i) Show the contents of Location 1 and Location 2 as binary using 8 bits.
Location 1
Location 2
[2]
(ii) Show the contents of Location 1 and Location 2 as hexadecimal.
Location 1
Location 2
[2]
(b) The following machine code instruction is stored in a location of main memory:
1
1
1
1
1
0
1
0
1
0
0
1
0
1
1
1
Convert this binary pattern into hexadecimal.
[4]
(c) Explain why a programmer would prefer to see the contents of the locations displayed as
hexadecimal rather than binary, when debugging his program that reads the key presses.
[2]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of
Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
© UCLES 2017
0478/01/SP/20
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Cambridge IGCSE®
0478/01
COMPUTER SCIENCE
Paper 1 Theory
For examination from 2020
MARK SCHEME
Maximum Mark: 75
Specimen
This document consists of 8 printed pages.
© UCLES 2017
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(a) 1 mark for the correct working in BOTH parts
1 mark for valid
1 mark for not valid
Identification number 1: working
= (4 × 6) + (2 × 5) + (1 × 4) + (9 × 3) + (2 × 2) + (3 × 1)
= 24 + 10 + 4 + 27 + 4 + 3
= 72 ÷ 11
= 6 remainder 6
valid/not valid: NOT valid
Identification number 2: working
= (8 × 6) + (2 × 5) + (0 × 4) + (1 × 3) + (5 × 2) + (6 × 1)
= 48 + 10 + 0 + 3 + 10 + 6
= 77 ÷ 11
= 7 remainder 0
valid/not valid: VALID
[3]
(b) 1 mark for correct working + 1 mark for check digit
working
= (5 × 6) + (0 × 5) + (2 × 4) + (4 × 3) + (1 × 2)
= 30 + 0 + 8 + 12 + 2
= 52
need to add 3 to make the total 55 (i.e. exactly divisible by 11)
check digit: 3
[2]
(c) 1 mark for each description and example
2
–
–
2 digits transposed
(e.g. 280419 becomes 280149/two digits have been switched)
incorrect digit
(e.g. 280419 becomes 250419/one of the digits has been mistyped)
[2]
direct access because of concentric tracks
can read and write at the same time because it has a read/write head
[2]
© UCLES 2017
0478/01/SM/20
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3
3
(a) 1 mark for each logic gate correctly connected
A
AND
NOT
Y
OR
T
AND
S
NOT
[5]
(b)
A
T
S
Y
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
}
]
]
]
]
1 mark
1 mark
1 mark
1 mark
[4]
4
(a) 1 mark for hours; 1 mark for minutes
1 6 : 4 9
1 mark 1 mark
[2]
(b) 1 mark for each digit
0
0
0
1
© UCLES 2017
0
1
0
0
0
1
1
0
1
1
0
1
1st digit
2nd digit
3rd digit
4th digit
[4]
0478/01/SM/20
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5
(c) Any two from:
– microprocessor compares present time with stored time
– if the values are the same
– sends signal to sound alarm
[2]
(a) Yes
[1]
(b) No
[1]
(c) –
–
6
www.dynamicpapers.com
re-reading the byte that was sent
request that the byte is resent
[2]
(a) Only answers:
– temperature (sensor)
– oxygen (sensor)
[2]
(b) Any four from:
– information from the sensors sent to microprocessor
– the ADC converts the analogue data into digital form
– if temperature < 25ºC OR temperature checked against stored value
– ...microprocessor sends signal to heater/actuator/valve...
– ...to switch on heater
– if oxygen level < 20 ppm OR oxygen level checked against stored value
– ...to open valve/oxygen supply
– use of DAC between microprocessor and devices
– sounds an alarm if system unable to respond
– continuously monitors sensor inputs
– any reference to feedback
[4]
(c) Any one from:
– unsafe limit stored in memory
– warning sound/signal if too high a value reached
– fail safe switch off in case of a malfunction
[1]
© UCLES 2017
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7
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(a)
authoring language used to
create documents to be viewed
on the World Wide Web
Browser
computer that responds to
requests to provide information
and services over the Internet
HTML
defines how messages are
transmitted and formatted
over the Internet
MAC address
numerical ID for each device
on the Internet
Internet Server
software that enables users
to access/view documents and
other resources on the Internet
IP address
unique ID for a network
interface card
http
5/6 matches – 5 marks
4 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
[5]
(b) any two from:
– to enable logon information to be kept on his computer
– to provide pages customised for Ahmed the next time he logs on
– to implement shopping carts and one-click purchasing
– to be able to distinguish between new and repeat visitors to the website
© UCLES 2017
0478/01/SM/20
[2]
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8
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(a) (i) Any one from:
– unit of data/memory
– 8 bits
– used to represent a character
(ii) 30
[1]
[1]
(b) Any two from:
Flash memory
– solid state memory
– no formatting issues
– plugs directly into the USB port
– direct transfer of data
CD-RW
– optical media
– slower access speed/flash memory has faster access speed
– requires a separate drive
– data needs to be burnt/finalised/finished (before being used on another device)
9
[2]
(a) Any one from:
– buffer
– RAM
[1]
(b) –
[1]
interrupt
10 (a) 1 mark for each correct word
(i) Hello World
[2]
(ii) Vmilozgu Rvwgyvg
[2]
(b) (i) Secure Socket Layer
[1]
(ii) the key itself is encrypted using strong encryption
© UCLES 2017
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[1]
7
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11
data loss caused by hard disk
head crash
anti-spyware software
hacking into files and changing or
deleting data
anti-virus software
introduction of software that
self-replicates and can cause
data loss
back-up files
reading of illegally accessed
documents
encryption
software that logs/records all
key presses on your computer
without you knowing
passwords and a firewall
5/4 matches – 4 marks
3 matches – 3 marks
2 matches – 2 marks
1 match – 1 mark
[4]
12 (a) code B
[1]
(b) Any one from:
– no need to understand workings of a computer
– easier to understand for programmer/closer to English
– much easier to debug
– much easier to test
– one-to-many when writing commands
– not machine-specific/portable
[1]
(c) Any one from:
– can address memory addresses directly
– no need for compilers/interpreters
– shorter code/code requires less storage/RAM
– can be written to run faster
[1]
© UCLES 2017
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8
(d) –
–
–
–
–
compiler produces object code / interpreter doesn’t produce object code
compiler translates whole program in one go / interpreter translates and executes line at
a time
compiler produces list of all errors / interpreter produces error message each time an
error encountered
compiler produces “stand alone code” / interpreter doesn’t produce “stand alone code”
compilation process is slow but resultant code runs very quickly / interpreted code runs
slowly
[2]
13 (a) (i)
Location 1
0
1
0
0
0
0
0
1
Location 2
0
1
0
0
0
0
1
1
[2]
(ii) 41
43
[2]
(b) FA97
[4]
(c) –
–
[2]
© UCLES 2017
easier to identify values
easier to spot errors
0478/01/SM/20
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Cambridge IGCSE™
* 6 0 8 9 4 1 6 9 5 3 *
COMPUTER SCIENCE
0478/12
February/March 2020
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Blank pages are indicated.
DC (CJ/CB) 186307/3
© UCLES 2020
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2
1
The Von Neumann model for a computer system uses components, such as registers and buses,
in the fetch-execute cycle.
(a) Draw a line to connect each component to its correct description.
Component
Description
Control Bus
Increments to point to the address of
the next instruction to be fetched
Program Counter (PC)
Holds the result of a calculation. It is
located within the Arithmetic Logic
Unit (ALU)
Memory Data Register
(MDR)
Carries signals to synchronise the
fetch-execute cycle
Accumulator (ACC)
Temporary storage between the
Central Processing Unit (CPU) and
primary memory
[3]
(b) State two buses, other than the control bus, used in the Von Neumann model for a computer
system.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
2
A school network is used to transmit and store data about students.
(a) Different types and methods of transmission can be used to send data across the network.
Three descriptions about data transmission are given.
Tick (3) one Method and tick (3) one Type for each description.
Method
Serial
(3)
Description
Parallel
(3)
Type
Simplex
(3)
Halfduplex
(3)
Duplex
(3)
Data is sent down a single wire in a
single direction only.
Data is sent down multiple wires in
both directions, at the same time.
Data is sent down a single wire in
both directions, but never at the
same time.
© UCLES 2020
0478/12/F/M/20
[3]
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3
(b) Parity bits are used to help detect errors in data transmission. A parity bit is added to each
binary value before transmission.
Three binary values are to be transmitted using even parity.
(i)
Complete the parity bit that would be added to each binary value for even parity.
Binary value
Parity bit
1
1
0
0
1
1
1
1
0
1
0
1
0
1
0
1
1
0
1
0
0
[3]
(ii)
A number of errors occurred during data transmission.
State why a parity check may not detect transmission errors.
...........................................................................................................................................
..................................................................................................................................... [1]
(c) Data is encrypted using 128-bit symmetric encryption before it is transmitted.
(i)
Explain what is meant by encryption.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
State how the strength of the encryption can be improved.
...........................................................................................................................................
..................................................................................................................................... [1]
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(d) Describe how the school could prevent the loss of stored data.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
3
Priya studies music at school. She is buying a new computer to complete her school work at home.
(a) Priya has a choice between an internal Hard Disk Drive (HDD) and an internal Solid State
Drive (SSD) to store data.
(i)
Give one similarity between an HDD and an SSD.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
Explain three differences between an HDD and an SSD.
1 ........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
2 ........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
3 ........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
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(b) Priya needs to transfer files between the school and her home computer.
Identify one off-line storage device she could use to transport the files.
............................................................................................................................................. [1]
(c) Priya is using sound editing software to record and edit different music tracks.
(i)
Identify two input devices she would use for this task.
Device 1 ............................................................................................................................
Device 2 ............................................................................................................................
[2]
(ii)
Identify two output devices she would use for this task.
Device 1 ............................................................................................................................
Device 2 ............................................................................................................................
[2]
(d) Priya shares her sound files with other students. Before sharing the sound files, she
compresses the files using lossless compression.
Describe how lossless compression reduces the size of a sound file.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(e) Priya currently uses MIDI files to store her music. Priya’s friends have asked her if they can
have an MP3 version of the file.
(i)
Give two features of a MIDI file.
1 ........................................................................................................................................
...........................................................................................................................................
2 ........................................................................................................................................
...........................................................................................................................................
[2]
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(ii)
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Give two features of an MP3 file.
1 ........................................................................................................................................
...........................................................................................................................................
2 ........................................................................................................................................
...........................................................................................................................................
[2]
4
Assemblers, compilers and interpreters are types of translators.
Tick (3) to show which statements apply to each translator. Each statement may apply to more
than one type of translator.
Assembler
(3)
Statement
Compiler
(3)
Interpreter
(3)
Translates low-level language to machine code
Translates high-level language to machine code
Produces error messages
Translates high-level language one line at a time
Produces an executable file
[5]
5
Programmers can use denary and hexadecimal values. These values are stored in a computer
system using binary.
(a) Explain why binary is used to store data in a computer system.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
© UCLES 2020
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(b) Complete the table to show how the denary value would be stored as binary in an 8-bit
register.
Denary value
8-bit register
129
56
[2]
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
(c) Complete the table to show how the hexadecimal value 3A9 would be stored as binary in a
12-bit register.
[3]
(d) Identify two uses of hexadecimal values in computer science.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
© UCLES 2020
0478/12/F/M/20
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6
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(a) Complete the truth table for the given logic circuit.
Do not attempt to simplify the logic circuit.
A
B
X
C
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2020
0478/12/F/M/20
9
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(b) A water control system uses a switch and two pressure sensors.
The outputs of the switch and sensors are shown in the table.
Sensor or Switch
Output of 1
Output of 0
Switch
(S1)
On
Off
Pressure Sensor
(P1)
>= 3
<3
Pressure Sensor
(P2)
>= 3
<3
Create a logic circuit that will produce an output (X) of 1 when:
The switch S1 is on
and
either P1 is less than 3 or P2 is less than 3, but not both.
All logic gates used must have a maximum of two inputs.
S1
P1
X
P2
[4]
© UCLES 2020
0478/12/F/M/20
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A room has an automatic lighting system. Electric lights are automatically turned on when a person
enters the room and the natural light level in the room is 10 or less.
Explain how sensors and a microprocessor are used to control the electric lights in the room.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [7]
© UCLES 2020
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A student website provides research support and software downloads.
(a) Students use a browser to access the web pages. Explain the role of a browser in this process.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [5]
(b) The website owners are worried about a denial of service (DoS) attack.
Explain the term denial of service attack.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(c) The website owners are also concerned about the ethical issues of copyright and plagiarism.
(i)
State what is meant by the term copyright.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
State what is meant by the term plagiarism.
...........................................................................................................................................
..................................................................................................................................... [1]
© UCLES 2020
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BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2020
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Cambridge IGCSE™
COMPUTER SCIENCE
0478/12
Paper 1
March 2020
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the March 2020 series for most Cambridge
IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.
This document consists of 14 printed pages.
© UCLES 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
March 2020
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These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
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PUBLISHED
March 2020
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GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2020
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0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(a)
Answer
Component
Description
Control Bus
Increments to point to the address
of the next instruction to be
fetched
Program Counter (PC)
Holds the result of a calculation. It
is located within the Arithmetic
Logic Unit (ALU)
Memory Data Register
(MDR)
Carries signals to synchronise the
fetch-execute cycle
Accumulator (ACC)
Temporary storage between the
Central Processing (CPU) and
primary memory
March 2020
www.dynamicpapers.com
Mark
3
1 mark for 1 correct line
2 marks for 2 correct lines
3 marks for 3/4 correct lines
1(b)
© UCLES 2020
Any two from:
• Address bus
• Data bus
2
Page 4 of 14
0478/12
Question
2(a)
March 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Mark
1 mark per each correct row:
3
Method
Description
Serial
()
Data is sent down a single wire in a single
direction only.
Parallel
()

Data is sent down multiple wires in both
directions, at the same time.
Simplex
()
© UCLES 2020
Duplex
()




1 mark for each correct parity bit:
3
Binary Value
2(b)(ii)
Halfduplex
()

Data is sent down a single wire in both
directions, but never at the same time.
2(b)(i)
Type
Parity Bit
1
1
0
0
1
1
1
1
1
0
1
0
1
0
1
0
0
1
1
0
1
0
0
1
Any one from:
• Transposition error // bits are interchanged
• Bits still add up to even number
• Even number of errors has occurred
1
Page 5 of 14
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
March 2020
www.dynamicpapers.com
Mark
2(c)(i)
Any two from:
• Scrambles data
• … making it meaningless/unintelligible
• Uses an algorithm / key
• Data / plain text is changed to cipher text
2
2(c)(ii)
Any one from:
• Increase the length of the key // use more than 128 bits
• Uses a more complex encryption algorithm
1
© UCLES 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(d)
© UCLES 2020
Answer
Any six from (max four for identification of method only):
March 2020
www.dynamicpapers.com
Mark
6
•
•
Backups
… if data is lost can be replaced
•
•
Install antivirus // Anti malware
… detects/deletes viruses that could corrupt/delete data
•
•
Install firewall
… helps prevent hackers gaining access and deleting/corrupting data
•
•
•
Password / Biometrics
Two factor authentication // two-step verification
… helps prevent unauthorised access and the deletion/corruption of data
•
•
Access rights
… helps prevent users accessing data they should not see and deleting it
•
•
Network/usage policy
… gives users guidance on data use // by example
•
•
•
Surge protection // Uninterrupted power supply (UPS)
… prevents loss of data that has not been saved
… prevents damage to hardware (that stores data)
•
•
Physical method // by example
… helps prevent unauthorised access and the deletion/corruption of data
Page 7 of 14
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
March 2020
www.dynamicpapers.com
Answer
Mark
3(a)(i)
Any one from:
• They are both non-volatile
• They are both secondary storage // Both not directly accessed by the CPU
• They both have a high capacity of storage
• Both have read and write abilities
1
3(a)(ii)
Any three from:
• HDD has moving parts but SSD does not
• HDD uses magnetic storage whereas SSD uses flash memory
• HDD is slower to access data than SSD // HDD has greater latency than SSD
• HDD will create noise/heat, whereas SSD runs quieter/cooler
• HDD has higher power consumption than SSD
• HDD have greater longevity/more read-write cycles whereas SDD has lower longevity/limited number of read-write cycles
• HDD larger in physical size/heavier than SSD
• HDD is normally cheaper for the same capacity of storage as SSD
• HDD is available in a larger storage capacity than SSD
3
Any one from:
• USB flash memory drive
• External HDD/SSD
• SD Card
• CD / DVD / Blu-ray
1
3(c)(i)
Any two from:
• Keyboard
• Mouse
• Microphone
• Touchscreen
2
3(c)(ii)
Any two from:
• Monitor / Screen
• Speakers
• Headphones
• Printer
2
3(b)
© UCLES 2020
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0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(d)
March 2020
www.dynamicpapers.com
Answer
Any two from:
• Uses a compression algorithm
• Does not permanently remove any data
• Repeated patterns of notes are identified …
• … and are grouped, with an index
Mark
2
NOTE: Other possible methods of lossless compression of sound can be credited
3(e)(i)
Any two from:
• Stores the notes played and not the sound
• Contains instructions/commands for digital instruments // Is recorded / played on a digital instrument e.g. synthesiser
• Stores data about notes e.g. pitch byte (Note: Two examples can be awarded)
• Can be a compressed format
• Can edit individual notes
2
3(e)(ii)
Any two from:
• Contains actual sound
• Contains samples of the sound wave
• Contains metadata // by example
• Uses lossy compression
• Recorded using microphone // Is recorded/played on an MP3 recorder/player
2
© UCLES 2020
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March 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
4
Mark
Assembler Compiler Interpreter
()
()
()
Statement

Translates low-level language to machine code
Translates high-level language to machine code
Produces error messages


()
()


Translates high-level language one line at a time
Produces an executable file
()
5




1 mark per each correct row:
NOTE: tick shown in brackets () is optional
Question
Answer
Mark
5(a)
Any two from:
• Computer consist of transistors / logic circuits
• … that can only store/process data in two states / as high-low / on-off / 1 and 0
2
5(b)
1 mark per each correct 8-bit binary value:
2
© UCLES 2020
Denary Value
8-bit binary register
129
10000001
56
00111000
Page 10 of 14
0478/12
Question
5(c)
Answer
0
1
1 mark
© UCLES 2020
Mark
1 mark per each correct conversion:
0
5(d)
March 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
1
1
3
0
1
0
1
0
0
1
1 mark
1 mark
Any two from:
• Represent colours in HTML // HTML colour codes
• MAC address
• Assembly Language
• Error messages
• IP address
• ASCII values
• URL
• Memory dump
• Memory locations
2
Page 11 of 14
0478/12
Question
6(a)
Answer
Working space
Mark
A
B
C
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
0
1
1
1
1
4 marks for 8 correct outputs
3 marks for 6/7 correct outputs
2 marks for 4/5 correct outputs
1 mark for 2/3 correct outputs
© UCLES 2020
March 2020
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Page 12 of 14
X
4
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(b)
March 2020
www.dynamicpapers.com
Answer
Mark
4
1 mark for each correct logic gate:
NOTE: Can also award 4 marks to a circuit that shows X = (P1 XOR P2) AND (S1)
Question
7
© UCLES 2020
Answer
Any seven from:
• Uses light sensor and Infrared / Motion / Pressure sensor
• Sensors send data to the microprocessor
• Data is converted from analogue to digital (using ADC)
• Microprocessor compares both values to stored values
• If motion value is out of range/in range, light value is checked // If light value is <= 10, motion value is checked
• If light value is <= 10 lights are turned on // If motion value is out of range/in range lights are turned on …
• … by sending a signal to actuator
• Lights remain on for set period (and then turn off) // If motion is in range/out of range or light is > 10 then signal sent to
turn lights off
• Process repeats / is continuous
Page 13 of 14
Mark
7
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
March 2020
www.dynamicpapers.com
Answer
Mark
8(a)
Any five from:
• Sends the URL of the website
• … to a DNS to find the IP address
• Connects to the webserver (using the IP address) …
• … using HTTP / HTTPS
• Renders/Translates the HTML
• Runs active/client-side scripts built into webpages
• Manages SSL/TLS certificate process
• Stores/retrieves cookies
5
8(b)
Any three from:
• Webserver is sent multiple requests // Requests flood the webserver …
• … at the same time
• Webserver crashes / runs slow
• Designed to prevent access to e.g. a website // Stops legitimate requests being processed/serviced
3
8(c)(i)
•
1
8(c)(ii)
Any one from:
• To claim other’s work as your own
• To use other people’s work without consent / acknowledgement
• Theft of intellectual property
© UCLES 2020
A law/legislation that requires permission to use intellectual property / other people’s work
Page 14 of 14
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Cambridge IGCSE™
* 9 1 1 9 7 5 8 2 3 8 *
COMPUTER SCIENCE
0478/12
May/June 2020
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Blank pages are indicated.
DC (CE/SW) 189019/3
© UCLES 2020
[Turn over
2
1
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A Von Neumann model for a computer system has a central processing unit (CPU) that makes
use of registers.
(a) Identify three registers that may be used.
Register 1 .................................................................................................................................
Register 2 .................................................................................................................................
Register 3 .................................................................................................................................
[3]
(b) The CPU is responsible for processing instructions.
One stage of processing instructions is the decode stage.
(i)
Identify the two other stages of processing instructions.
Stage 1 ..............................................................................................................................
Stage 2 ..............................................................................................................................
[2]
(ii)
Identify the component of the CPU that is responsible for decoding instructions.
..................................................................................................................................... [1]
2
Both an interpreter and a compiler can be used when writing a program in a high-level language.
(a) Explain why a programmer would make use of both an interpreter and a compiler.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
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(b) Give three reasons why a programmer would choose to write a program in a high-level
language, instead of a low-level language.
Reason 1 ..................................................................................................................................
...................................................................................................................................................
Reason 2 ..................................................................................................................................
...................................................................................................................................................
Reason 3 ..................................................................................................................................
...................................................................................................................................................
[3]
3
A company collects and stores data about its customers. The data is stored on a server in the
company’s office.
The data is transmitted to cloud storage to create a back-up.
The data is encrypted using symmetric encryption before it is sent to the cloud storage.
(a) Describe how the data is encrypted.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) Give three other methods that can be used to secure the data in the office.
Method 1 ...................................................................................................................................
...................................................................................................................................................
Method 2 ...................................................................................................................................
...................................................................................................................................................
Method 3 ...................................................................................................................................
...................................................................................................................................................
[3]
© UCLES 2020
0478/12/M/J/20
[Turn over
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4
4
(a) Identify the name and draw the single logic gate that can replace the given logic circuits.
(i)
A
X
B
Name of gate: ……………………………
Drawing of gate:
[2]
(ii)
A
X
B
Name of gate: ……………………………
Drawing of gate:
[2]
(b) Complete the truth table for the given logic statement:
X = (((A OR C) AND (NOT A AND NOT C)) XOR B)
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2020
0478/12/M/J/20
5
5
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Meena uses a browser to research information for her business.
(a) Give three functions of a browser.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
(b) Meena buys products for her business using the Internet.
The Transport Layer Security (TLS) protocol is used for transferring data when she buys
products.
One layer of the TLS protocol is the handshake layer.
(i)
Describe the purpose of the handshake layer.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
Identify the other layer of the TLS protocol.
..................................................................................................................................... [1]
(iii)
Identify another protocol that can be used to transfer data securely.
..................................................................................................................................... [1]
(c) Meena visits a website to buy products for her business.
The browser uses a small file to store the details of the products she views. This allows the
website to display advertisements for other products she may like.
The small file also stores her log-in details.
Give the name of this type of file.
............................................................................................................................................. [1]
© UCLES 2020
0478/12/M/J/20
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6
6
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Six statements are given about touch screen technology.
Tick (3) to show if the statement applies to Capacitive or Resistive touch screen technology.
Capacitive
(3)
Statement
Resistive
(3)
Needs pressure to be applied to create a circuit
May not register a touch if the user is wearing gloves
More commonly used in smartphones
More responsive to a touch
Needs an electrical field to be changed to register a touch
Cheaper to manufacture
[6]
© UCLES 2020
0478/12/M/J/20
7
7
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(a) Give the denary value of each of the three 12-bit binary values.
(i)
000000001100
..................................................................................................................................... [1]
(ii)
000011000110
..................................................................................................................................... [1]
(iii)
010011000001
..................................................................................................................................... [1]
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
(b) 12-bit binary values can also be represented as hexadecimal values.
Give the hexadecimal value of the 12-bit binary value.
000011101001
............................................................................................................................................. [3]
© UCLES 2020
0478/12/M/J/20
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8
8
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Leonard has a new laser printer to print letters for his business.
Leonard connects his printer to his computer using the USB port.
(a) Give three benefits of using the USB port to connect the printer to the computer.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
Benefit 3 ...................................................................................................................................
...................................................................................................................................................
[3]
(b) State two benefits and one drawback of Leonard using a laser printer, instead of an inkjet
printer, to print the letters.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
Drawback ..................................................................................................................................
...................................................................................................................................................
[3]
(c) An interrupt signal is sent from the printer to the computer.
(i)
Give two examples of when a printer would generate an interrupt signal.
Example 1 .........................................................................................................................
Example 2 .........................................................................................................................
[2]
(ii)
Many devices send interrupt signals.
Identify the software in the computer that will receive and manage all interrupt signals.
..................................................................................................................................... [1]
© UCLES 2020
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9
9
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(a) Six statements are given about storage devices.
Tick (3) to show if the statement applies to hard disk drive (HDD) storage or
solid state drive (SSD) storage.
Some statements can apply to both.
Statement
HDD
(3)
SSD
(3)
It has a limited number of read/write cycles
It uses magnetic properties to store data
It has moving parts
It is non-volatile storage
It can be used as an external storage device to back up data
It uses flash memory to store data
[6]
(b) Optical storage is another type of storage.
Give two examples of optical storage.
Example 1 .................................................................................................................................
Example 2 .................................................................................................................................
[2]
© UCLES 2020
0478/12/M/J/20
[Turn over
10
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10 Uma is concerned about risks that she may encounter when using the Internet.
Two of the risks she is concerned about are phishing and pharming.
(a) Give one similarity and two differences between phishing and pharming.
Similarity ...................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Difference 1 ..............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Difference 2 ..............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
(b) Identify two other risks that Uma could encounter when using the Internet.
Risk 1 ........................................................................................................................................
Risk 2 ........................................................................................................................................
[2]
© UCLES 2020
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(c) Uma uses a firewall to secure the data on her computer.
(i)
Uma tells her friend that a firewall can only be software-based.
Tick (3) to show whether Uma is Correct or Incorrect.
Correct
Incorrect
(ii)
[1]
Describe how the firewall helps to keep Uma’s data secure.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
© UCLES 2020
0478/12/M/J/20
12
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2020
0478/12/M/J/20
www.dynamicpapers.com
Cambridge IGCSE™
COMPUTER SCIENCE
0478/12
Paper 1
May/June 2020
MARK SCHEME
Maximum Mark: 75
Published
Students did not sit exam papers in the June 2020 series due to the Covid-19 global pandemic.
This mark scheme is published to support teachers and students and should be read together with the
question paper. It shows the requirements of the exam. The answer column of the mark scheme shows the
proposed basis on which Examiners would award marks for this exam. Where appropriate, this column also
provides the most likely acceptable alternative responses expected from students. Examiners usually review
the mark scheme after they have seen student responses and update the mark scheme if appropriate. In the
June series, Examiners were unable to consider the acceptability of alternative responses, as there were no
student responses to consider.
Mark schemes should usually be read together with the Principal Examiner Report for Teachers. However,
because students did not sit exam papers, there is no Principal Examiner Report for Teachers for the June
2020 series.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the June 2020 series for most Cambridge
IGCSE™ and Cambridge International A & AS Level components, and some Cambridge O Level
components.
This document consists of 10 printed pages.
© UCLES 2020
[Turn over
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2020
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2020
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PUBLISHED
May/June 2020
www.dynamicpapers.com
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2020
Page 3 of 10
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(a)
Answer
Any three from:
− MAR
− MDR // MBR
− PC // IAR // NIR // SCR
− ACC
− CIR // IR
− IAS
May/June 2020
www.dynamicpapers.com
Marks
3
1(b)(i)
−
−
Fetch
Execute
2
1(b)(ii)
−
Control unit
1
Question
Answer
Marks
2(a)
Any four from:
− To translate the high-level language into low-level language
− Interpreter used whilst writing the program
− Interpreter used to debug code line by line
− Compiler used when program completed
− Compiler used to create separate executable file (so compiler no longer needed)
− If it runs first time in a compiler there are no syntax errors
4
2(b)
Any three from:
− Easier to understand // Don’t know assembly code
− Easier to debug
− Easier to maintain
− Portable
− Knowledge of manipulating memory locations/registers not required
− Can use an IDE
− Greater range of languages
3
© UCLES 2020
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0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
May/June 2020
www.dynamicpapers.com
Marks
3(a)
Any four from:
− Encryption key is used
− Encryption algorithm is used
− Encryption key / algorithm is applied to plain text
− … to convert it into cypher text
− Same key is used to encrypt and decrypt the text
4
3(b)
Any three from:
− Firewall
− Password
− Proxy server
− Physical methods (by example e.g. CCTV, Locks)
− Access rights
− Asymmetric encryption
− Disconnect from network
3
Question
Answer
Marks
4(a)(i)
−
NAND
2
4(a)(ii)
−
NOR
2
© UCLES 2020
Page 5 of 10
0478/12
Question
4(b)
May/June 2020
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Working space
Marks
A
B
C
X
0
0
0
0
0
0
1
0
0
1
0
1
0
1
1
1
1
0
0
0
1
0
1
0
1
1
0
1
1
1
1
1
4
4 marks for 8 correct outputs
3 marks for 6 or 7 correct outputs
2 marks for 4 or 5 correct outputs
1 mark for 2 or 3 correct outputs
Question
5(a)
© UCLES 2020
Answer
Any three from:
− Convert HTML code
− Display web pages
− Check if a website is secure
− Request web pages from a web server
− Send URL/domain name
− Runs active script
− Store history/favourites/bookmarks
− Create tabs
Marks
3
Page 6 of 10
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May/June 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
Marks
5(b)(i)
−
−
Carries out authentication of server and client
Handles encryption algorithms / keys
2
5(b)(ii)
−
Record layer
1
5(b)(iii)
5(c)
Any one from:
− SSL
− HTTPS
−
1
1
Cookies
Question
Answer
6
Marks
Capacitive
()
Statement

Needs pressure to be applied to create a circuit
May not register a touch if the user is wearing
gloves

More commonly used in smartphones

More responsive to a touch

Needs an electrical field to be changed to
register a touch


Cheaper to manufacture
One mark per correct tick
© UCLES 2020
Resistive
()
Page 7 of 10
6
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
May/June 2020
www.dynamicpapers.com
Marks
7(a)(i)
−
12
(ignore leading zeros)
1
7(a)(ii)
−
198
(ignore leading zeros)
1
7(a)(iii)
−
1217
7(b)
1
One mark per each correct hex value in correct order
− 0E9
Question
3
Answer
Marks
8(a)
Any three from:
− It is a universal standard
− It can’t be inserted the wrong way around
− Supports different transmission speeds
− Automatically detects if correct driver installed
3
8(b)
Two marks for benefits, one mark for drawback
Benefits:
− Faster speed of printing
− Can print duplex / on both sides
− Many letters can be printed from one toner cartridge
− Can print in high volumes
Drawback
− Toner cartridge more expensive to buy
− More time to warm-up
− Larger footprint
3
© UCLES 2020
Page 8 of 10
0478/12
Question
8(c)(i)
May/June 2020
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Marks
2
Any two from:
− Paper jam
− Out of paper
− Out of toner/ink
− Buffer full
− Awaiting input
− Print complete
− Printer ready
Award any other valid example
8(c)(ii)
Any one from:
− Operating system
− Interrupt handler
− Interrupt service routine
Question
1
Answer
9(a)
Marks
HDD
()
Statement

It has a limited number of read/write cycles
It uses magnetic properties to store data

It has moving parts

It is non-volatile storage


It can be used as an external storage device to back-up data



It uses flash memory to store data
© UCLES 2020
SSD
()
Page 9 of 10
6
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
9(b)
Answer
Any two from:
− CD (drive)
− DVD (drive)
− Blu-ray (drive)
Question
10(a)
May/June 2020
www.dynamicpapers.com
Marks
2
Answer
One mark for similarity, two marks for differences
Similarity:
− Both are designed to steal personal data
− They both pose as a real company/person
Differences:
− Pharming uses malicious code installed on hard drive
− Phishing is in form of an email
− Phishing requires use to follow a link / open an attachment
Marks
3
10(b)
−
−
Virus
Malware
2
10(c)(i)
−
Incorrect
1
10(c)(ii)
© UCLES 2020
Any four from:
− Can help prevent hacking
− Can monitor incoming and outgoing traffic
− Can set criteria / rules are set for traffic
− Can check whether traffic meets / defies criteria rules
− Can rejects any traffic that does not meet / defies criteria
Page 10 of 10
4
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Cambridge IGCSE™
* 4 1 2 4 5 5 1 0 3 7 *
COMPUTER SCIENCE
0478/13
May/June 2020
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Blank pages are indicated.
DC (JC/CT) 186484/3
© UCLES 2020
[Turn over
2
1
www.dynamicpapers.com
Pradeep is reading hexadecimal values for a project he is working on.
(a) The first three hexadecimal values he reads are 15, 102 and A9.
Give the denary values for the three hexadecimal values.
15 ..............................................................................................................................................
102 ............................................................................................................................................
A9 .............................................................................................................................................
[3]
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
(b) Pradeep has two 8-bit binary values that he needs to convert to hexadecimal values for his
project.
Give the hexadecimal values for the two 8-bit binary values.
01010000 ..................................................................................................................................
00111101 ..................................................................................................................................
[4]
© UCLES 2020
0478/13/M/J/20
www.dynamicpapers.com
3
2
(a) Six hardware devices are shown.
Tick (✓) to show if each hardware device is an Input, Output or Storage device.
Hardware device
Input
(✓)
Output
(✓)
Storage
(✓)
Solid state drive (SSD)
Sensor
Headphones
Microphone
USB flash drive
Actuator
[6]
(b) Genevieve writes a paragraph about a barcode reader.
Using the list given, complete the paragraph. Not all terms in the list need to be used.
•
•
•
•
•
•
•
•
•
actuators
binary
black
input
microprocessors
output
sensors
storage
white
A barcode reader is an ............................................... device. It shines a light at the barcode
and the light is reflected back. The ............................................... bars in the barcode reflect
less light than the ............................................... bars.
............................................... are used to capture the amount of reflected light and the
different reflections are converted to ............................................... values.
© UCLES 2020
0478/13/M/J/20
[5]
[Turn over
4
3
www.dynamicpapers.com
Thomas has an online business that sells homemade furniture. He has a web server that hosts his
website for his business.
(a) Describe the role of a web browser in requesting and displaying the web pages for the
website.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) Thomas is worried about a denial of service (DoS) attack on his web server.
Describe what happens in a denial of service attack.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
© UCLES 2020
0478/13/M/J/20
5
4
www.dynamicpapers.com
The table shows four definitions.
Complete the table giving the missing Term for each definition.
Term
Definition
A data transmission method that sends data
one bit at a time, down a single wire
An address given to a device on a network.
The address is assigned by the network
The software used to render HTML and display
a web page
An address given to a device at the
manufacturing stage that can be used to
identify the device on a network
[4]
© UCLES 2020
0478/13/M/J/20
[Turn over
6
5
www.dynamicpapers.com
(a) A clothing shop uses a barcode reader at the checkout.
The checkout is linked to a stock control system. The system monitors stock levels and
automatically keeps them above a minimum level.
Explain how the stock control system automatically keeps the stock levels above a minimum
level.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) The software for the stock control system is stored on a central computer. The computer uses
random access memory (RAM), read only memory (ROM) and a hard disk drive (HDD).
The computer is a Von Neumann model computer system with a central processing
unit (CPU).
(i)
State the purpose of the RAM, ROM and HDD in the central computer.
RAM ..................................................................................................................................
...........................................................................................................................................
ROM ..................................................................................................................................
...........................................................................................................................................
HDD ..................................................................................................................................
...........................................................................................................................................
[3]
(ii)
Identify four components that are part of the CPU.
Component 1 .....................................................................................................................
Component 2 .....................................................................................................................
Component 3 .....................................................................................................................
Component 4 .....................................................................................................................
[4]
© UCLES 2020
0478/13/M/J/20
7
6
www.dynamicpapers.com
Consider the given logic statement:
X = (((A XOR B) AND C) OR NOT C)
(a) Draw a logic circuit to match the given logic statement.
All logic gates must have a maximum of two inputs. Do not attempt to simplify the logic
statement.
A
B
X
C
[4]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2020
0478/13/M/J/20
[Turn over
8
7
www.dynamicpapers.com
Edie uses a firewall to help prevent her children from accessing websites that she does not want
them to see.
(a) Describe how the firewall helps prevent her children from accessing these websites.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) Edie is concerned that her children may download a virus when accessing websites.
State what is meant by a virus and explain what could happen if a virus was downloaded.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(c) Edie explains to her children how to identify if a website is secure.
(i)
Give two ways that her children can identify if a website is secure.
1 ........................................................................................................................................
2 ........................................................................................................................................
[2]
© UCLES 2020
0478/13/M/J/20
9
(ii)
www.dynamicpapers.com
Describe how a browser checks that a website is secure.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
8
Six statements are given about printers.
Tick (✓) to show whether the statement applies to a 3D printer, an Inkjet printer or a Laser printer.
Some statements apply to more than one printer.
3D
(✓)
Statement
Inkjet
(✓)
Laser
(✓)
Uses a moving print head
Uses liquid ink
Produces output using materials such as plastic and resin
Uses piezoelectric or thermal technology
Uses a rotating drum to transfer the image to the paper
Uses layer upon layer of material to create the output
[6]
© UCLES 2020
0478/13/M/J/20
[Turn over
10
9
www.dynamicpapers.com
Four 7-bit binary values are being transmitted from one computer to another. An odd parity check
is being used to check for errors in the binary values.
Write the correct Parity bit for each 7-bit binary value to make sure it meets odd parity.
Parity bit
7-bit binary value
.....................
0000011
.....................
1000000
.....................
0111111
.....................
1010101
[4]
10 Clive has a laptop computer that he uses for his business. He enters a username and password to
log in to his laptop.
Clive is worried about spyware being used to find out his username and password.
(a) Describe how spyware could be used to find out Clive’s username and password.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) The threat of spyware makes Clive concerned about typing a password to log in to his laptop.
Give an example of how Clive could log in securely without typing a password.
............................................................................................................................................. [1]
© UCLES 2020
0478/13/M/J/20
11
BLANK PAGE
© UCLES 2020
0478/13/M/J/20
www.dynamicpapers.com
12
www.dynamicpapers.com
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2020
0478/13/M/J/20
www.dynamicpapers.com
Cambridge IGCSE™
COMPUTER SCIENCE
0478/13
Paper 1
May/June 2020
MARK SCHEME
Maximum Mark: 75
Published
Students did not sit exam papers in the June 2020 series due to the Covid-19 global pandemic.
This mark scheme is published to support teachers and students and should be read together with the
question paper. It shows the requirements of the exam. The answer column of the mark scheme shows the
proposed basis on which Examiners would award marks for this exam. Where appropriate, this column also
provides the most likely acceptable alternative responses expected from students. Examiners usually review
the mark scheme after they have seen student responses and update the mark scheme if appropriate. In the
June series, Examiners were unable to consider the acceptability of alternative responses, as there were no
student responses to consider.
Mark schemes should usually be read together with the Principal Examiner Report for Teachers. However,
because students did not sit exam papers, there is no Principal Examiner Report for Teachers for the June
2020 series.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the June 2020 series for most Cambridge
IGCSE™ and Cambridge International A & AS Level components, and some Cambridge O Level
components.
This document consists of 10 printed pages.
© UCLES 2020
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
May/June 2020
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2020
Page 2 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
May/June 2020
www.dynamicpapers.com
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2020
Page 3 of 10
0478/13
Question
1(a)
1(b)
May/June 2020
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
−
−
−
Marks
3
21
258
169
1 mark for each correct hex value
− 50
− 3D
4
Question
Answer
2(a)
Marks
Input
()
Hardware device
Output
()

Solid state drive (SSD)

Sensor

Headphones

Microphone

USB flash drive

Actuator
One mark for each correct tick
© UCLES 2020
Storage
()
Page 4 of 10
6
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(b)
Answer
−
−
−
−
−
May/June 2020
www.dynamicpapers.com
Marks
5
Input
Black
White
Sensors
Binary
One mark for each correct term in the correct place
Question
Answer
Marks
3(a)
Any three from:
− Sends request to webserver
− Receives web pages back from webserver
− Converts HTML to display web page
− Manages protocols
3
3(b)
Any three from:
− Many requests are sent from a computer
− Requests are sent to the webserver
− The webserver becomes flooded with traffic
− The webserver cannot handle the requests / fails
− The website can no longer be accessed
− Attack maybe distributed
3
Question
4
© UCLES 2020
Answer
−
−
−
−
Marks
4
Serial (ignore any ref to simplex etc.)
IP (address)
Browser
MAC (address)
Page 5 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(a)
5(b)
5(c)
© UCLES 2020
Answer
Any four from:
− Stock control system has a database of stock
− Each product has a (unique) barcode
− Barcode is scanned, and product looked up in database
− Stock levels for product are reduced (by 1)
− Stock is checked against minimum level
− If stock at/below minimum level an order is placed
− When stock is re-ordered flag is reset
−
−
−
It has RAM to store the data / programs / by example currently in use
It has ROM to permanently store the boot up instructions
It has HDD to store the stock database / software / OS / by example
Any four from:
− MAR
− MDR
− PC
− ALU
− CU
− ACC
− CIR
− Buses
− Registers
May/June 2020
www.dynamicpapers.com
Marks
4
3
4
Page 6 of 10
0478/13
May/June 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
Marks
4
6(a)
A
B
X
C
One mark for each correct gate.
© UCLES 2020
Page 7 of 10
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
6(b)
Question
May/June 2020
www.dynamicpapers.com
Answer
Working space
Marks
A
B
C
0
0
0
1
0
0
1
0
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
Answer
X
4
Marks
7(a)
Any four from:
− Examines outgoing traffic to check what is being requested
− Examines incoming traffic to check the content of what is being received
− Sets rules/criteria for websites that can/cannot be accessed // creates a blacklist
− Check if traffic meets/does not meet rules/criteria
− If it does/does not, access to website granted/denied
4
7(b)
Any three from:
− Software that can replicate itself
− It could cause the computer to crash / run slow / generate errors
− It could delete/damage files
− It could fill up the storage space
− It could stop the hardware being able to communicate
− It could spread to other devices on the network
3
© UCLES 2020
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May/June 2020
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
Marks
7(c)(i)
Any two from:
− Locked padlock
− HTTPS
− View the certificate
2
7(c)(ii)
Any four from:
− requests web server to identify itself/view the (SSL) certificate
− receives a copy of the (SSL) certificate, sent from the webserver
− checks if (SSL) certificate is authentic/trustworthy
− sends signal back to webserver that the certificate is authentic/trustworthy
− starts to transmit data once connection is established as secure
4
Question
Answer
8
Statement
Uses a moving print head
Marks
3D
()
Inkjet
()



Uses liquid ink
Produces output using materials such as plastic and resin
Uses piezoelectric or thermal technology

()
Uses layer upon layer of material to create the output
One mark per each correct row.
Page 9 of 10


Uses a rotating drum to transfer the image to the paper
© UCLES 2020
Laser
()

6
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
9
Answer
−
−
−
−
10(a)
10(b)
© UCLES 2020
Answer
Any four from:
− Example of spyware e.g. Keylogger is used
− Spyware is downloaded without knowledge (by example)
− Spyware records key presses / screen clicks / screen activity
− Data is relayed back to third party
− Data is analysed // Patterns in data could reveal log-in details …
− … details can then be used to log into the laptop (remotely)
−
−
Marks
4
1
0
1
1
Question
May/June 2020
www.dynamicpapers.com
Marks
4
1
Biometric device
Two step authentication
Page 10 of 10
www.dynamicpapers.com
Cambridge IGCSE™
* 4 1 9 2 4 0 4 4 3 3 *
COMPUTER SCIENCE
0478/11
October/November 2020
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Blank pages are indicated.
DC (LK) 186555/3
© UCLES 2020
[Turn over
www.dynamicpapers.com
2
1
Six devices are shown.
Tick (3) to show if each device is an Input, Output or Storage device.
Input
(3)
Device
Output Storage
(3)
(3)
Keyboard
Sensor
3D cutter
2D scanner
Microphone
Hard disk drive (HDD)
[6]
2
Ron is attending a music concert. He has bought three tickets.
Each ticket number is displayed as a hexadecimal number.
(a) Complete the table to show the 12-bit binary values and the Denary values for each
Hexadecimal ticket number.
Hexadecimal
ticket number
12-bit binary value
Denary value
028
1A9
20C
[6]
Working space
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
© UCLES 2020
0478/11/O/N/20
3
www.dynamicpapers.com
(b) Each ticket also has a QR code. The QR code is scanned at the entrance to the venue.
A person can only enter the venue with a valid QR code that allows entry.
When a person enters, a count is incremented to show how many people have entered the
venue.
Explain how the system scans the QR code, checks if a person can enter and counts how
many people have entered.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [7]
3
Transport Layer Security (TLS) protocol is used to secure the transmission of data over the
Internet.
(a) Identify the two layers in the TLS protocol.
Layer 1 ......................................................................................................................................
Layer 2 ......................................................................................................................................
[2]
© UCLES 2020
0478/11/O/N/20
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4
www.dynamicpapers.com
(b) The following paragraph explains how data is sent securely using the TLS protocol.
Use the terms to complete the paragraph. Not all terms may need to be used.
•
•
•
•
•
•
•
•
•
authentic
binary
browser
certificate
internet service provider
signal
web page
web server
website
The browser requests the .................................................................... to identify itself
by providing its .................................................................... . This is sent and a check
is performed to see if it is .................................................................... . If it is, the
................................................................... sends a ...................................................................
back to the web server and data transmission begins.
[5]
(c) Identify one other protocol that can be used to secure data transmission over the Internet.
............................................................................................................................................. [1]
© UCLES 2020
0478/11/O/N/20
5
www.dynamicpapers.com
Question 4 starts on page 6.
© UCLES 2020
0478/11/O/N/20
[Turn over
6
4
www.dynamicpapers.com
Consider the given logic statement:
X = ((NOT (A NAND B)) OR (B NOR C))
(a) Draw a logic circuit to represent the given logic statement.
All logic gates must have a maximum of two inputs. Do not attempt to simplify the logic
statement.
A
B
X
C
[4]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2020
0478/11/O/N/20
www.dynamicpapers.com
7
(c) The logic statement given has four different logic gates.
Identify two other logic gates and complete a truth table for each.
Logic gate
......................................
Truth table
A
B
0
0
0
1
1
0
1
1
Logic gate
......................................
X
Truth table
A
B
0
0
0
1
1
0
1
1
X
[4]
5
Luke is creating a website for his t-shirt design business.
(a) He is using HTML to create the website. HTML can be separated into structure and
presentation.
(i)
Give two examples of HTML structure.
Example 1 .........................................................................................................................
Example 2 .........................................................................................................................
[2]
(ii)
Give two examples of HTML presentation.
Example 1 .........................................................................................................................
Example 2 .........................................................................................................................
[2]
© UCLES 2020
0478/11/O/N/20
[Turn over
8
www.dynamicpapers.com
(b) Luke is concerned that his web server may be hacked or subjected to a denial of service
(DoS) attack.
State two security methods that Luke could use to help protect the web server from hacking
or a DoS attack.
Method 1 ...................................................................................................................................
Method 2 ...................................................................................................................................
[2]
6
A Von Neumann model for a computer system contains several integrated circuits (IC).
(a) Parallel data transmission is used in an IC.
(i)
Describe how data is transmitted using parallel data transmission.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
Give one benefit of using parallel, rather than serial, data transmission.
...........................................................................................................................................
..................................................................................................................................... [1]
(b) The computer has a central processing unit (CPU).
(i)
Identify the bus that carries signals around the CPU to control the components.
..................................................................................................................................... [1]
(ii)
Identify the register built into the arithmetic logic unit (ALU).
..................................................................................................................................... [1]
© UCLES 2020
0478/11/O/N/20
9
(iii)
www.dynamicpapers.com
Four statements about a Von Neumann model for a computer system are shown.
Tick (3) to show if each statement is True or False.
True
(3)
Statement
False
(3)
Data and instructions are stored in the same memory unit
The control unit manages operations within the CPU
Data and instructions can be fetched into the CPU at the same time
The control unit is responsible for decoding an instruction
[4]
7
Nina is recording some music tracks that she has written. She is researching whether she should
record them in MIDI or MP3 format.
Explain what is meant by MIDI and MP3 format.
MIDI ..................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
MP3 ..................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[4]
© UCLES 2020
0478/11/O/N/20
[Turn over
10
8
www.dynamicpapers.com
Matthew is buying a new television with a display that uses LED technology.
(a) Explain what is meant by LED technology.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) State three benefits of LED technology.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
Benefit 3 ...................................................................................................................................
...................................................................................................................................................
[3]
(c) Identify one other technology that could have been used for the display.
............................................................................................................................................. [1]
9
Victoria is entering data into a computer system. The data will be transmitted to cloud storage.
(a) An even parity check is used to check for errors in the binary values after transmission.
For each of the 7-bit binary values, write the Parity bit that makes sure even parity is met.
© UCLES 2020
7-bit binary value
Parity bit
1100010
......................
1001011
......................
0100010
......................
0010111
......................
0478/11/O/N/20
[4]
11
www.dynamicpapers.com
(b) Identify two other error checking methods that could be used to check the binary values are
correct after transmission.
Method 1 ...................................................................................................................................
Method 2 ...................................................................................................................................
[2]
(c) A check digit is used to check whether data is correct when entered into the system.
Describe how a check digit can be used to make sure the data entered is correct.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
© UCLES 2020
0478/11/O/N/20
12
www.dynamicpapers.com
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2020
0478/11/O/N/20
www.dynamicpapers.com
Cambridge IGCSE™
COMPUTER SCIENCE
0478/11
Paper 1
October/November 2020
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2020 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and some
Cambridge O Level components.
This document consists of 11 printed pages.
© UCLES 2020
[Turn over
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
October/November 2020
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2020
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PUBLISHED
October/November 2020
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GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2020
Page 3 of 11
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
Input
()
Keyboard

Sensor

6
Output
()
Storage
()

3D Cutter
2D Scanner

Microphone


Hard disk drive (HDD)
Question
2(a)
Answer
Marks
One mark for each correct binary conversion
One mark for each correct denary conversion
Hexadecimal
ticket number
© UCLES 2020
Marks
One mark per each correct row:
Device
October/November 2020
www.dynamicpapers.com
12-bit binary value
6
Denary value
028
0000 0010 1000
40
1A9
0001 1010 1001
425
20C
0010 0000 1100
524
Page 4 of 11
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(b)
Answer
Seven from:
− Camera captures code // Laser/light shone on code
− Black squares reflect different light to white
− Corner squares are used for alignment
− Pattern converted to digital data // by example
− (Digital) data sent to microprocessor
− There is a database of valid QR codes
− Data compared to stored values/valid QR codes …
− … If data matches entry is granted is raised
− … If data matches count is incremented
− … If data does not match, entry is denied
Question
−
−
Handshake
Record
3(b)
−
−
−
−
−
Web server
Certificate
Authentic
Browser
Signal
3(c)
Any one from:
− SSL
− HTTPS
© UCLES 2020
Marks
7
Answer
3(a)
October/November 2020
www.dynamicpapers.com
Marks
2
5
1
Page 5 of 11
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
4(a)
Marks
4
One mark for each correct gate with correct input
© UCLES 2020
October/November 2020
www.dynamicpapers.com
Page 6 of 11
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(b)
© UCLES 2020
Answer
October/November 2020
www.dynamicpapers.com
Marks
4
Four marks for 8 correct outputs
Three marks for 6/7 correct outputs
Two marks for 4/5 correct outputs
One mark for 2/3 correct outputs
Working space
A
B
C
X
0
0
0
1
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
1
1
0
1
0
1
1
0
1
1
1
1
1
Page 7 of 11
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(c)
Answer
One mark for the correct gate and one mark for the correct truth table
−
−
October/November 2020
www.dynamicpapers.com
Marks
4
AND
A
B
X
0
0
0
0
1
0
1
0
0
1
1
1
A
B
X
0
0
0
0
1
1
1
0
1
1
1
0
XOR
Question
Answer
Marks
5(a)(i)
−
Two valid examples of Structure e.g. where text is placed, margins of page
2
5(a)(ii)
−
Two valid examples of Presentation e.g. font size, font colour
2
5(b)
−
−
Firewall
Proxy server
2
© UCLES 2020
Page 8 of 11
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
October/November 2020
www.dynamicpapers.com
Answer
Marks
6(a)(i)
−
−
Uses multiple wires
Sends multiple bits of data at a time
2
6(a)(ii)
−
Faster transmission speed
1
6(b)(i)
−
Control (bus)
1
6(b)(ii)
−
Accumulator (ACC)
1
6(b)(iii)
True
()
Statement
Data and instructions are stored in the same memory unit

The control unit manages operations within the CPU


Data and instructions can be fetched into the CPU at the same time
The control unit is responsible for decoding an instruction
© UCLES 2020
Page 9 of 11
False
()

4
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7
Answer
Four from (Max two per format):
October/November 2020
www.dynamicpapers.com
Marks
4
MIDI
− Musical Instrument Digital Interface (file)
− Stores a set of commands/instructions (for how the sound should be played)
− Does not store the actual sounds
− Data in the file has been recorded using digital instruments // produced by synthesizer
− Specifies pitch of the note // specifies the note to be played
− Specifies when each note plays and stops playing // Specifies key on/off
− Specifies duration of the note
− Specifies volume of the note
− Specifies the tempo
− Specifies the type of instrument
− Individual notes can be edited
MP3
− MP3 is a format for digital audio
− MP3 is an actual recording of the sound
− MP3 is a (lossy) compression format
− Recorded using a microphone
Question
8(a)
Answer
Marks
Any three from:
− Light emitting diodes (technology)
− The display is made up of pixels
− … that are arranged together as a matrix
− … each is formed of three LEDs/filters
− Shades of colour are achieved by mixing red, blue and green
− The screen can be back-lit/edge-lit
3
NOTE: Use of liquid crystals with LED technology can also be awarded
© UCLES 2020
Page 10 of 11
0478/11
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2020
www.dynamicpapers.com
Marks
8(b)
Any three from:
− Energy efficient // low power consumption
− Long lasting // longevity
− Focussed beam // less light strays from beam
− Brighter/vivid colours
− High resolution
− No flicker
− Display is thinner
− Mercury free technology // environmentally friendly
− Fewer pixel failure
− Increased viewing in sunlight
3
8(c)
−
1
LCD
Question
Answer
Marks
9(a)
−
−
−
−
9(b)
Two from:
− Checksum
− Automatic repeat request // ARQ
2
9(c)
Any four from:
− Data is input with check digit
− A calculation is performed on the (inputted) data // by example
− The calculated digit is compared to a stored value
− If it matches, the data entered is correct
− If it does not match, the data entered is incorrect
4
© UCLES 2020
4
1
0
0
0
Page 11 of 11
www.dynamicpapers.com
Cambridge IGCSE™
* 1 8 6 8 6 1 8 8 1 5 *
COMPUTER SCIENCE
0478/12
October/November 2020
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Blank pages are indicated.
DC (LK) 186556/2
© UCLES 2020
[Turn over
2
1
www.dynamicpapers.com
Tina is creating a website for charity events. She uses HTML to create the website.
(a) State what is meant by HTML.
...................................................................................................................................................
............................................................................................................................................. [1]
(b) She uses the hexadecimal colour code #43B7F0 as the background colour for her website.
(i)
State whether background colour is an example of structure or presentation, in the
website.
..................................................................................................................................... [1]
(ii)
The hexadecimal colour code #43B7F0 is stored in three 8-bit registers.
Give the 8-bit binary values for each part of the hexadecimal code.
43
B7
F0
[6]
(c) Tina uses a microphone to record a welcome message for her website.
(i)
State whether the microphone is an input or output device.
..................................................................................................................................... [1]
© UCLES 2020
0478/12/O/N/20
3
(ii)
www.dynamicpapers.com
She wants to compress the recording to make sure that the file is as small as possible
for the website.
Identify which type of compression she should use and describe how this would compress
the file for the website.
Type of compression .........................................................................................................
Description
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(iii)
Give two benefits of compressing the file for the website.
Benefit 1 ............................................................................................................................
...........................................................................................................................................
Benefit 2 ............................................................................................................................
...........................................................................................................................................
[2]
© UCLES 2020
0478/12/O/N/20
[Turn over
4
www.dynamicpapers.com
(d) Tina will use the TLS protocol in her website when selling tickets to people for different charity
events. This makes sure that their personal data is transmitted securely.
(i)
Identify the two layers that are present in the TLS protocol.
Layer 1 ..............................................................................................................................
Layer 2 ..............................................................................................................................
[2]
(ii)
Explain how data is sent securely using the TLS protocol.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [6]
© UCLES 2020
0478/12/O/N/20
www.dynamicpapers.com
5
(e) Tina is concerned about security threats to her web server.
(i)
Identify three security threats to her web server that Tina might be concerned about.
1 ........................................................................................................................................
2 ........................................................................................................................................
3 ........................................................................................................................................
[3]
(ii)
Tina installs a proxy server to help protect her website from security threats.
Describe how the proxy server will help protect the website.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
2
Four 7-bit binary values are transmitted from one computer to another. A parity bit was added
to each binary value creating 8-bit binary values. All the binary values have been transmitted
correctly.
(a) Tick (✓) to show whether an Even or an Odd parity check has been used for each binary
value.
8-bit binary value
Even
(✓)
Odd
(✓)
11111111
01100110
01111011
10000000
[4]
© UCLES 2020
0478/12/O/N/20
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6
www.dynamicpapers.com
(b) The data will also be checked using a checksum.
Describe how a checksum can be used to check that the data has been transmitted correctly.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [5]
3
Alessandro has some important data stored on his computer.
He is concerned about accidental damage to his data.
(a) (i)
Identify three ways that the data could be accidentally damaged.
1 ........................................................................................................................................
2 ........................................................................................................................................
3 ........................................................................................................................................
[3]
(ii)
State what Alessandro could do to make sure that he can retrieve his data if it is
accidentally damaged.
..................................................................................................................................... [1]
© UCLES 2020
0478/12/O/N/20
7
www.dynamicpapers.com
(b) Alessandro uses an SSD to store his data.
Describe what is meant by an SSD and how it operates to store data.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(c) Alessandro also uses off-line storage to store his data.
Three examples of off-line storage are Blu-ray, CD and DVD.
Six statements are given about off-line storage.
Tick (✓) to show if each statement applies to Blu-ray, CD, or DVD.
Some statements apply to more than one example of off-line storage.
Blu-ray
(✓)
Statement
CD
(✓)
DVD
(✓)
A type of optical storage
Has the largest storage capacity
Can be dual layer
Read using a red laser
Has the smallest storage capacity
Stores data in a spiral track
[6]
© UCLES 2020
0478/12/O/N/20
[Turn over
8
4
www.dynamicpapers.com
Consider the logic statement:
X = (((A NAND B) NOR (B AND C)) OR C)
(a) Draw a logic circuit to match the given logic statement.
All logic gates must have a maximum of two inputs. Do not attempt to simplify the logic
statement.
A
B
X
C
[4]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2020
0478/12/O/N/20
9
5
www.dynamicpapers.com
Tammy is buying a new computer that has an LED display.
(a) Five statements about LED displays are given.
Tick (✓) to show if each statement is True or False.
Statement
True
(✓)
False
(✓)
It is a flat panel display
It creates images using red, green and blue diodes
It is not very energy efficient and gives off heat
It can be used in mobile devices such as smartphones and tablets
It is a front-lit display
[5]
© UCLES 2020
0478/12/O/N/20
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10
www.dynamicpapers.com
(b) Tammy connects the computer to her home network. The computer has a MAC address and
an IP address.
A paragraph is given about MAC addresses and IP addresses.
Complete the paragraph using the list of terms given. Not all terms need to be used.
•
•
•
•
•
•
•
•
•
•
compiled
computer
control
dynamic
identify
packet
principal
protocol
similar
unique
A MAC address is a media access …………………………………………………….. address.
A network device has a ……………………………………………………… MAC address that
can help ………………………………………………. the device in the network. An IP address
is an Internet ………………………………………… address. An IP address can be static or
…………………………………………… .
[5]
(c) Tammy uses a browser when accessing the Internet.
Describe the role of the browser.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
© UCLES 2020
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© UCLES 2020
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12
www.dynamicpapers.com
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2020
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www.dynamicpapers.com
Cambridge IGCSE™
COMPUTER SCIENCE
0478/12
Paper 1
October/November 2020
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2020 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and some
Cambridge O Level components.
This document consists of 13 printed pages.
© UCLES 2020
[Turn over
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
October/November 2020
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2020
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PUBLISHED
October/November 2020
www.dynamicpapers.com
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2020
Page 3 of 13
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(a)
Answer
October/November 2020
www.dynamicpapers.com
Marks
Any one from:
− Hypertext Mark-up Language
− Web authoring language // language used to write/create websites/web pages
1
1(b)(i)
−
1
1(b)(ii)
One mark per each nibble:
1(c)(i)
© UCLES 2020
Presentation
6
43
0
1
0
0
0
0
1
1
B7
1
0
1
1
0
1
1
1
F0
1
1
1
1
0
0
0
0
−
1
Input
Page 4 of 13
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Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(c)(ii)
October/November 2020
www.dynamicpapers.com
Answer
One from:
− Lossy (compression)
Marks
4
Any three from:
− A (compression) algorithm is used
− Removes redundant/unnecessary data from the file
− Removes sounds that cannot be heard by the human ear/background noise
− Reduces sample rate
− Reduces sample resolution
− Data is permanently removed // original file cannot be re-instated
− Perceptual music shaping is used
NOTE: If lossless given, marks can be awarded for a correct description of lossless as follow through.
Any three from (lossless):
− A (compression) algorithm is used
− Repeating patterns are identified
− … are replaced with a value
− … and indexed
− No data is permanently removed // original file can be re-instated
− Suitable example of a lossless algorithm
1(c)(iii)
Any two from:
− Quicker for her to upload
− Quicker for users to download
− Won’t slow website down as much when loading
− Takes up less storage space
2
1(d)(i)
−
−
2
© UCLES 2020
Handshake (layer)
Record (layer)
Page 5 of 13
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
October/November 2020
www.dynamicpapers.com
Answer
Marks
1(d)(ii)
Any six from:
− Client/browser requests secure connection to server
− Client/browser requests the server to identify itself
− Server provides a digital certificate
− Client/browser validates the certificate
− Client/browser send signal back to server (to begin transmission)
− Session caching can be used
− A session key is generated
− Encryption method is agreed // data is encrypted
6
1(e)(i)
Any three from:
− Hacking
− Denial of service (DoS) attack
− Virus
− Malware
3
NOTE: Three different type of malware can be awarded
1(e)(ii)
© UCLES 2020
Any four from:
− Acts as a firewall
− Monitor/filters/examines incoming and outgoing traffic
− Rules/criteria for traffic can be set // blacklist/whitelist set
− Blocks any traffic that does not meet criteria …
− … and can send a warning message to the user
− Stop the website failing in a DoS attack // DoS attack hits the proxy server and not the webserver
Page 6 of 13
4
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(a)
Answer
One mark for each correct row:
8-bit binary value
Even
()
11111111

01100110

01111011

10000000
2(b)
© UCLES 2020
October/November 2020
www.dynamicpapers.com
Marks
4
Odd
()

Any five from:
− A value is calculated from the data
− The value is calculated using an algorithm // by example
− The value is appended to the data to be transmitted
− Value is recalculated after transmission
− Values are compared
− If the values match the data is correct // if the values do not match the data is incorrect
Page 7 of 13
5
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(a)(i)
October/November 2020
www.dynamicpapers.com
Answer
Any three from:
− Loss of power/electricity
− Spillage of liquids
− Flood
− Fire
− Human error
− Hardware failure
− Software failure
Marks
3
NOTE: Three different types of human error can be awarded e.g. accidental deletion, not saving data, incorrect shutdown
procedure
3(a)(ii)
3(b)
−
1
Create a backup
Max three from:
− Solid state drive
− Non-volatile
− Secondary storage
− Flash memory
− Has no mechanical/moving parts
− Uses transistors
− … and cells that are laid out in a grid
− Uses control gates and floating gates
− Can be NAND/NOR (technology)
− Use EEPROM technology
4
Max two from:
− Stores data by flashing it onto the chips
− Data stored by controlling the flow of electrons through/using transistors/chips/gates
− The electric current reaches the control gate and flows through to the floating gate to be stored
− When data is stored the transistor is converted from 1 to 0
© UCLES 2020
Page 8 of 13
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(c)
Answer
One mark for each correct row:
CD
()
DVD
()
A type of optical storage



Has the largest storage capacity

Can be dual layer

© UCLES 2020

Read using a red laser

Has the smallest storage capacity

Stores data in a spiral track
Marks
6
Blu-ray
()
Statement
October/November 2020
www.dynamicpapers.com




Page 9 of 13
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(a)
© UCLES 2020
Answer
One mark for each correct logic gate with correct input:
October/November 2020
www.dynamicpapers.com
Marks
4
Page 10 of 13
0478/12
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(b)
© UCLES 2020
Answer
October/November 2020
www.dynamicpapers.com
Marks
Four marks for 8 correct outputs
Three marks for 6/7 correct outputs
Two marks for 4/5 correct outputs
One mark for 2/3 correct outputs
4
A
B
C
Working space
X
0
0
0
0
0
0
1
1
0
1
0
0
0
1
1
1
1
0
0
0
1
0
1
1
1
1
0
1
1
1
1
1
Page 11 of 13
0478/12
Question
5(a)
Answer
Marks
One mark for each correct row:
5
True
()
Statement
It is a flat panel display

It creates images using red, green and blue diodes

It is also used in mobile devices such as smartphones and tablets


It is a front-lit display
© UCLES 2020
False
()

It is not very energy efficient and gives off heat
5(b)
October/November 2020
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
One mark for each correct term in the correct place:
− Control
− Unique
− Identify
− Protocol
− Dynamic
5
Page 12 of 13
0478/12
Question
5(c)
© UCLES 2020
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
Any four from:
− Allows user to view web pages
− Renders HTML
− Allows user to bookmark/favourite web pages
− Provides navigation features
− Allows (multiple) tabs
− Stores cookies
− Records history of pages visited
− Has a homepage
− Runs active script
− Allows files to be downloaded from website/internet
− Sends a request to the IP address/web server (to obtain the contents of a web page)
− Sends URL to DNS
− Manages HTTP/HTTPS protocol
Page 13 of 13
October/November 2020
www.dynamicpapers.com
Marks
4
www.dynamicpapers.com
Cambridge IGCSE™
* 6 3 5 3 6 1 2 9 0 4 *
COMPUTER SCIENCE
0478/13
October/November 2020
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Blank pages are indicated.
DC (PQ) 186557/2
© UCLES 2020
[Turn over
2
1
www.dynamicpapers.com
Five hardware devices are given.
Tick (3) to show if each device is an Input, Output or Storage device.
Device
Input
(3)
Output
(3)
Storage
(3)
Solid state drive (SSD)
Headphones
2D cutter
LCD projector
Microphone
[5]
2
Paige has a computer that has a central processing unit (CPU) based on the Von Neumann model
for a computer system.
(a) Identify the component within the CPU that controls the flow of data.
............................................................................................................................................. [1]
(b) Identify the component within the CPU where calculations are carried out.
............................................................................................................................................. [1]
(c) Identify the component within the CPU that stores the address of the next instruction to be
processed.
............................................................................................................................................. [1]
(d) Identify the register within the CPU that holds an instruction that has been fetched from
memory.
............................................................................................................................................. [1]
(e) Identify the register within the CPU that holds data that has been fetched from memory.
............................................................................................................................................. [1]
© UCLES 2020
0478/13/O/N/20
www.dynamicpapers.com
3
3
(a) Four denary to 8-bit binary conversions are given.
Tick (3) to show if each denary to 8-bit binary conversion is Correct or Incorrect.
Denary
Binary Conversion
145
10010001
179
10110101
11
00010011
100
01100010
Correct
(3)
Incorrect
(3)
[4]
(b) Convert the 12-bit binary number into hexadecimal.
1
1
0
0
0
1
0
0
0
0
0
0
............................................................................................................................................. [3]
4
Eugene has a web server that stores his online shopping website.
Customers access the website using a browser.
(a) Describe how the webpages are requested and displayed on the customer’s computer.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) State three online security threats to Eugene’s web server.
Threat 1 ....................................................................................................................................
Threat 2 ....................................................................................................................................
Threat 3 ....................................................................................................................................
[3]
© UCLES 2020
0478/13/O/N/20
[Turn over
4
5
www.dynamicpapers.com
Arjun uses a scanner to create digital versions of some printed documents.
The scanner is attached to his computer using a USB connection.
(a) Tick (3) to show if the USB connection uses Parallel or Serial data transmission.
Describe your chosen method of data transmission.
Parallel
Serial
Description
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
(b) Give three benefits of a USB connection.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
Benefit 3 ...................................................................................................................................
...................................................................................................................................................
[3]
(c) Arjun uses the Internet to send the digital documents to his friend. He wants to make sure the
documents are sent securely.
Identify two protocols that can be used to transfer data securely.
Protocol 1 .................................................................................................................................
Protocol 2 .................................................................................................................................
[2]
© UCLES 2020
0478/13/O/N/20
5
6
www.dynamicpapers.com
Elsa writes a paragraph in an examination about encryption.
There are several terms missing from the paragraph.
Complete the paragraph using the list of given terms. Not all terms may need to be used.
Some terms may be used more than once.
•
•
•
•
•
•
•
•
algorithm
alphanumeric
cookie
cypher
key
padlock
plain
word processed
The data is encrypted using a ....................................................................... . This is an
....................................................................... that is used to scramble the data. The data before
encryption is known as ....................................................................... text. When the data has been
encrypted it is known as ....................................................................... text. To read the encrypted
data it needs to be decrypted using a ....................................................................... .
© UCLES 2020
0478/13/O/N/20
[5]
[Turn over
www.dynamicpapers.com
6
7
Four 7-bit binary values are transmitted from one computer to another. A parity bit was added
to each binary value creating 8-bit binary values. All the binary values have been transmitted
correctly.
(a) Tick (3) to show whether an Even or an Odd parity check has been used for each binary
value.
8-bit binary value
Even
(3)
Odd
(3)
10000001
10000010
00101001
00101000
[4]
(b) A parity check may not always detect errors that have occurred in data transmission.
State why a parity check may not detect data transmission errors.
............................................................................................................................................. [1]
(c) Give one other error checking method that could be used to check for errors in data
transmission.
............................................................................................................................................. [1]
© UCLES 2020
0478/13/O/N/20
7
8
www.dynamicpapers.com
Edith is buying a new computer monitor that displays images using LCD technology.
(a) Explain what is meant by LCD technology.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) State three benefits of LCD technology.
Benefit 1 ...................................................................................................................................
...................................................................................................................................................
Benefit 2 ...................................................................................................................................
...................................................................................................................................................
Benefit 3 ...................................................................................................................................
...................................................................................................................................................
[3]
9
Elle uses both CDs and DVDs to store her school projects.
(a) Give three similarities between a CD and a DVD.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
3 ................................................................................................................................................
...................................................................................................................................................
[3]
(b) State one difference between a CD and a DVD.
...................................................................................................................................................
............................................................................................................................................. [1]
© UCLES 2020
0478/13/O/N/20
[Turn over
8
www.dynamicpapers.com
10 Consider the following logic statement:
X = ((B AND NOT A) XOR (A OR C))
(a) Draw a logic circuit to match the given logic statement.
All logic gates must have a maximum of two inputs. Do not attempt to simplify the logic
statement.
A
B
X
C
[4]
(b) Complete the truth table for the given logic statement.
A
B
C
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Working space
X
[4]
© UCLES 2020
0478/13/O/N/20
9
11
www.dynamicpapers.com
A theme park has a game where a player tries to run from the start to the finish without getting wet.
The system for the game uses sensors and a microprocessor to spray water at a player as they
run past each sensor.
Describe how the sensors and the microprocessor are used in this system.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [6]
12 Warner says that he has a very good Internet Service Provider (ISP) that provides several services.
Five statements about ISPs are given.
Tick (3) to show if each statement is True or False.
True
(3)
Statement
False
(3)
Provides access to the Internet for customers
Can determine the maximum bandwidth available for customers
Monitors the volume of data downloaded by customers
Can provide an IP address for the customer
Stores the content for all web pages available on the Internet
[5]
© UCLES 2020
0478/13/O/N/20
[Turn over
10
www.dynamicpapers.com
13 Phishing and pharming are two security issues a user should be aware of when using the Internet.
(a) State one similarity between phishing and pharming.
...................................................................................................................................................
............................................................................................................................................. [1]
(b) Explain two differences between phishing and pharming.
Difference 1 ...............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Difference 2 ..............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
© UCLES 2020
0478/13/O/N/20
11
BLANK PAGE
© UCLES 2020
0478/13/O/N/20
www.dynamicpapers.com
12
www.dynamicpapers.com
BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2020
0478/13/O/N/20
www.dynamicpapers.com
Cambridge IGCSE™
COMPUTER SCIENCE
0478/13
Paper 1
October/November 2020
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the October/November 2020 series for most
Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and some
Cambridge O Level components.
This document consists of 13 printed pages.
© UCLES 2020
[Turn over
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Generic Marking Principles
October/November 2020
www.dynamicpapers.com
These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these
marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the
scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.
© UCLES 2020
Page 2 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
October/November 2020
www.dynamicpapers.com
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.
© UCLES 2020
Page 3 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1
Answer
One mark for each correct row:
Device
Input
()
Marks
5
Output
()
Storage
()

Solid state drive (SSD)
Headphones

2D cutter

LCD projector

Microphone
October/November 2020
www.dynamicpapers.com

Question
Answer
Marks
2(a)
−
Control unit // CU
1
2(b)
−
Arithmetic logic unit // ALU
1
2(c)
−
Program counter // memory address register // PC // MAR
1
2(d)
−
Memory data register // current instruction register // MDR // CIR
1
2(e)
−
Memory data register // MDR
1
© UCLES 2020
Page 4 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
3(a)
3(b)
Question
4(a)
© UCLES 2020
October/November 2020
www.dynamicpapers.com
Answer
One mark per each correct row:
Marks
4
Denary
Binary Conversion
Correct
()
Incorrect
()
145
10010001

179
10110101

11
00010011

100
01100010

One mark for each correct conversion in the correct order:
− C
− 4
− 0
Answer
Any four from:
− Browsers sends URL to DNS
− … using HTTP
− DNS finds matching IP addresses for URL
− … and sends IP address to web browser
− Web browser sends request to IP address/web server for web pages
− Web pages are sent from web server to browser
− Browser renders HTML to display web pages
− Any security certificates are exchanged/authenticated // SSL/HTTPS is used to secure the data
− … encrypting any data sent
Page 5 of 13
3
Marks
4
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
4(b)
Answer
Any three from:
− Hacking
− Denial of service (DoS)
− Malware
− Virus
October/November 2020
www.dynamicpapers.com
Marks
3
NOTE: three suitable types of malware can be awarded
Question
5(a)
Answer
One mark for correct tick, two marks for description
−
Serial
−
−
Bits sent one at a time
Single wire
Marks
3
If parallel given, no mark for parallel, but follow through for correct description of parallel:
−
−
5(b)
© UCLES 2020
Multiple bits sent at a time
Multiple wires
Any three from:
− Universal connection // industry standard
− Can only be inserted one way
− Backward compatible
− Auto configures // automatically recognised devices
− Can power devices
− Fast data transfer speed
− Inexpensive to purchase/manufacture
Page 6 of 13
3
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
5(c)
Answer
Any two from:
− TLS
− SSL
− HTTPS
Answer
−
−
−
−
−
Answer
One mark for each correct row:
8-bit binary value
Even
()
10000001

10000010

7(b)
© UCLES 2020
Marks
4
Odd
()

00101001
00101000
Marks
5
Key // Algorithm
Algorithm // Key (must be opposite of first one)
Plain
Cypher
Key // Algorithm
Question
7(a)
Marks
2
Question
6
October/November 2020
www.dynamicpapers.com

Any one from:
− Transposition error
− When bits still add up to odd/even number
− Even number of incorrect bits
1
Page 7 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
7(c)
Answer
Any one from:
− ARQ
− Checksum
Question
October/November 2020
www.dynamicpapers.com
Marks
1
Answer
Marks
8(a)
Any three from:
− Liquid crystal display
− The display is made of pixels
− … arranged in a matrix
− Uses a flat panel display
− Backlit display
− … with CCFLs/LEDs
− Uses light-modulating properties of liquid crystals
− Crystals can be turned between opaque and transparent (to allow light to pass)
− Colours created using RGB
3
8(b)
Any three from:
− Low power consumption
− Runs at cool temperature
− Do not suffer image burn
− Do not suffer flicker issues
− Bright image/colours
− High resolution image
− Cheaper to purchase than e.g. LED screen
3
© UCLES 2020
Page 8 of 13
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2020
www.dynamicpapers.com
Marks
9(a)
Any three from:
− Both need a red laser to read/write data
− Both are spun to be read
− Both use spiral tracks for data
− Both are optical storage
− Both are off-line storage // both non-volatile
− Both use pits and lands to store data
3
9(b)
Any one from:
− DVD can be dual layer, but CD can only be single
− DVD has higher storage capacity
− DVD has a shorter wavelength laser
− DVD are spun faster
− DVDs have a higher data transfer rate
1
© UCLES 2020
Page 9 of 13
0478/13
Question
10(a)
© UCLES 2020
Cambridge IGCSE – Mark Scheme
PUBLISHED
Answer
One mark for each correct logic gate with the correct input:
Page 10 of 13
October/November 2020
www.dynamicpapers.com
Marks
4
0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
10(b)
11
© UCLES 2020
Answer
October/November 2020
www.dynamicpapers.com
Marks
4
Four marks for 8 correct outputs
Three marks for 6/7 correct outputs
Two marks for 4/5 correct outputs
One mark for 2/3 correct outputs
Working space
A
B
C
X
0
0
0
0
0
0
1
1
0
1
0
1
0
1
1
0
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
1
Six from:
− Suitable sensor used e.g. motion sensor/pressure sensor
− (Analogue) data is converted to digital (using ADC)
− Sensor sends data to microprocessor
− Data compared to stored data …
− … if value outside range/within range water is sprayed
− … signal sent to actuator to spray water
− … if value within range/outside range no action taken
− Continuous loop
Page 11 of 13
6
0478/13
Question
12
Answer
Marks
One mark for each correct row:
5
True
()
Statement
Provides access to the Internet for customers

Can determine the maximum bandwidth available for customers

Monitors the volume of data downloaded by customers

Can provide an IP address for the customer

Stores the content for all web pages available on the Internet
© UCLES 2020
October/November 2020
www.dynamicpapers.com
Cambridge IGCSE – Mark Scheme
PUBLISHED
Page 12 of 13
False
()

0478/13
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
October/November 2020
www.dynamicpapers.com
Marks
13(a)
Any one from:
− Both are designed to steal/collect personal data
− Both pretend to be a real company
− Both use fake websites
1
13(b)
−
−
2
© UCLES 2020
Phishing involves use of an email whereas pharming involves installing malicious code
Phishing involves clicking a link or an attachment whereas pharming creates a redirection
Page 13 of 13
www.dynamicpapers.com
Cambridge IGCSE™
* 0 8 0 3 7 2 8 9 4 0 *
COMPUTER SCIENCE
0478/12
February/March 2021
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 16 pages. Any blank pages are indicated.
DC (PQ/SG) 202679/4
© UCLES 2021
[Turn over
2
1
www.dynamicpapers.com
A hockey club records the number of people that watch each match. An 8-bit binary register is
used to store this value.
(a) 46 people watch the first match and 171 people watch the second match.
Show how the registers would store these denary values as 8-bit binary.
Denary
value
8-bit binary
46
171
[2]
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
(b) Give the largest denary value that can be stored in the 8-bit binary register.
............................................................................................................................................. [1]
(c) The hockey club wants to increase the number of people that can watch each match to 2000.
The 8-bit binary register may no longer be able to store the value.
Give the smallest number of bits that can be used to store the denary value 2000.
............................................................................................................................................. [1]
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
© UCLES 2021
0478/12/F/M/21
3
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(d) Electronic data about the final score for the match is transmitted to a central computer
30 kilometres away, using serial transmission.
(i)
Explain why serial transmission is more appropriate than parallel transmission in this
scenario.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(ii)
The data transmission is also half-duplex.
Describe half-duplex data transmission.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(iii)
The data transmission uses checksums.
Describe how checksums are used to detect errors in data transmission.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
© UCLES 2021
0478/12/F/M/21
[Turn over
4
2
www.dynamicpapers.com
Gurdeep takes high definition photographs using a digital camera. She has set up a website where
users can view thumbnails of her photographs. A thumbnail is a small version of the high definition
photograph.
(a) Gurdeep compresses the high definition photographs to create the thumbnails. She uses
lossy compression.
Describe how lossy compression creates the thumbnails.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) Gurdeep sets up a web server to host her website. She reads about an Internet Protocol (IP)
address, a Media Access Control (MAC) address and a Uniform Resource Locator (URL).
Draw a line to connect each term to the correct example.
Term
Example
IP address
192.168.0.255
MAC address
https://www.cambridgeinternational.org
URL
00:15:E9:2B:99:3C
[2]
© UCLES 2021
0478/12/F/M/21
5
www.dynamicpapers.com
(c) Users can buy the high definition photographs from the website. When a user buys a high
definition photograph, a Secure Socket Layer (SSL) connection is created.
(i)
Give one benefit of using an SSL connection.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
Explain how the SSL connection is created.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
© UCLES 2021
0478/12/F/M/21
[Turn over
6
3
www.dynamicpapers.com
The given table shows the name or description of four devices. The table is incomplete.
Complete the missing device names and descriptions.
Device name
Description
...................................................
Uses either thermal bubble or piezoelectric technology
...............................................................................................
Actuator
...............................................................................................
...............................................................................................
...............................................................................................
...................................................
Uses thousands of tiny mirrors that can move very quickly to
create an image
...............................................................................................
Mouse
...............................................................................................
...............................................................................................
...............................................................................................
[4]
© UCLES 2021
0478/12/F/M/21
7
4
www.dynamicpapers.com
A supermarket sells many products. Each product has a barcode.
(a) Explain how the barcode is read at the supermarket checkout and how the price of the product
is found.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
(b) The supermarket stores data using a Solid State Drive (SSD).
(i)
Explain how an SSD stores data.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(ii)
One advantage of an SSD rather than a Hard Disk Drive (HDD) is that it has no moving
parts, so it is more durable.
State one other advantage of the supermarket using SSD rather than HDD.
...........................................................................................................................................
..................................................................................................................................... [1]
© UCLES 2021
0478/12/F/M/21
[Turn over
www.dynamicpapers.com
8
5
Computers use logic gates.
(a) State the single logic gate that produces each truth table.
Truth table
Logic gate
A
B
Output
0
0
1
0
1
1
1
0
1
1
1
0
A
B
Output
0
0
0
0
1
1
1
0
1
1
1
0
A
B
Output
0
0
1
0
1
0
1
0
0
1
1
0
...................................................................................
...................................................................................
...................................................................................
[3]
(b) An aeroplane has a warning system that monitors the height of the aeroplane above the
ground, whether the aeroplane is ascending or descending, and the speed of the aeroplane.
© UCLES 2021
Input
Binary value
Condition
Height
(H)
1
Height is less than 500 metres
0
Height is greater than or equal to 500 metres
Ascending or
Descending
(A)
1
Aeroplane is ascending or in level flight
0
Aeroplane is descending
Speed
(S)
1
Speed is less than or equal to 470 knots
0
Speed is greater than 470 knots
0478/12/F/M/21
9
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The warning system will produce an output of 1 that will sound an alarm (W) when either of
these conditions apply:
Height is less than 500 metres and the aeroplane is descending
or
The aeroplane is descending and speed is greater than 470 knots
Draw a logic circuit to represent the warning system.
H
A
W
S
[5]
© UCLES 2021
0478/12/F/M/21
[Turn over
10
6
www.dynamicpapers.com
Hacking is one type of Internet risk used to obtain personal data that is stored on a computer.
(a) Explain how a firewall can help prevent hacking.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(b) Identify and describe two other types of internet risk that are used to obtain personal data.
Internet risk 1 ............................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
Internet risk 2 ............................................................................................................................
Description ................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[6]
© UCLES 2021
0478/12/F/M/21
11
7
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Adeel has used a high-level language to program a mobile application.
(a) Describe what is meant by a high-level language.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(b) Adeel uses an interpreter while developing and testing the application.
Adeel uses a compiler when the application is ready to be shared with others.
Compare the features of interpreters and compilers.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(c) Adeel is considering distributing his application as free software or shareware.
Explain the difference between free software and shareware.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [5]
© UCLES 2021
0478/12/F/M/21
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12
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(d) Adeel is concerned about his application being plagiarised.
Define the term plagiarism.
...................................................................................................................................................
............................................................................................................................................. [1]
(e) Adeel copyrights his application.
State why Adeel copyrights his application.
...................................................................................................................................................
............................................................................................................................................. [1]
© UCLES 2021
0478/12/F/M/21
13
8
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The Von Neumann model, for a computer system, uses the stored program concept.
(a) Describe what is meant by the stored program concept.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
(b) The fetch-execute cycle of a Von Neumann model, for a computer system, uses registers and
buses.
(i)
Describe the role of the Program Counter.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(ii)
Describe the role of the Control Bus.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(c) Computers based on the Von Neumann model, for a computer system, use interrupts.
Explain why interrupts are needed.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
© UCLES 2021
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© UCLES 2021
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15
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© UCLES 2021
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16
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BLANK PAGE
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2021
0478/12/F/M/21
www.dynamicpapers.com
Cambridge IGCSE™
COMPUTER SCIENCE
0478/12
Paper 1
March 2021
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the March 2021 series for most Cambridge
IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.
This document consists of 10 printed pages.
© UCLES 2021
[Turn over
0478/12
Cambridge IGCSE – Mark Scheme
March 2021
www.dynamicpapers.com
PUBLISHED
Generic Marking Principles
These general marking principles must be applied by all examiners when marking candidate answers.
They should be applied alongside the specific content of the mark scheme or generic level descriptors
for a question. Each question paper and mark scheme will also comply with these marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit
is given for valid answers which go beyond the scope of the syllabus and mark scheme,
referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these
features are specifically assessed by the question as indicated by the mark scheme. The
meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently, e.g. in situations where candidates have not followed
instructions or in the application of generic level descriptors.
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question
(however; the use of the full mark range may be limited according to the quality of the candidate
responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should
not be awarded with grade thresholds or grade descriptors in mind.
© UCLES 2021
Page 2 of 10
Cambridge IGCSE – Mark Scheme
March 2021
www.dynamicpapers.com
PUBLISHED
0478/12
Question
1(a)
Answer
Marks
1 mark each
2
Denary Value
8-bit binary
46
0
0
1
0
1
1
1
0
171
1
0
1
0
1
0
1
1
1(b)
−
255
1
1(c)
−
11
1
1(d)(i)
Any three from:
− More accurate/reliable/efficient over long distances
− Less chance of interference / cross talk
− …that will skew / distort the data // less likely to get errors
− Data will arrive in order
− Serial is cheaper to purchase/install/maintain
3
1(d)(ii)
−
−
2
1(d)(iii)
Any three from:
− Calculates a value from the bits/data (to be transferred) // by
example/description
− Value is appended to the bits/data
− Value is transferred with the bits/data
− Receiver recalculates the checksum
− If both values are different error is detected // if both values are the same
the transmission is successful
Question
2(a)
© UCLES 2021
Transmission in both directions …
…not at the same time // asynchronous
Answer
Any three from:
− A compression algorithm is used
− Data will be lost/deleted permanently // original file cannot be recreated
− Reduce the range of colours used / colour depth / bits per pixel
− Reduce the number of pixels / image resolution removes data that will not
be noticed by the user // removes unnecessary data
Page 3 of 10
3
Marks
3
Cambridge IGCSE – Mark Scheme
March 2021
www.dynamicpapers.com
PUBLISHED
0478/12
Question
2(b)
Answer
1 mark for 1 line, 2 marks for 3 lines
Term
Marks
2
Details
IP address
192.168.0.255
MAC address
https://www.cambridgeinternational.org
URL
00:15:E9:2B:99:3C
2(c)(i)
−
2(c)(ii)
Four from:
− Uses (digital) certificates
− ….requested from web server by browser/client // browser/client asks web
server to identify itself
− Server send SSL/digital signature to browser/client
− Client and server agree on encryption method to use
− … that contains the server's public key
− Browser checks authenticity of certificate…
− … then session key is generated
− … the transaction will begin // sends signal to server to start transmission
© UCLES 2021
Data if intercepted cannot be understood // Data is encrypted // Data is
scrambled // uses keys to encode/decode data
Page 4 of 10
1
4
Cambridge IGCSE – Mark Scheme
March 2021
www.dynamicpapers.com
PUBLISHED
0478/12
Question
3
Answer
One mark for each device/description
Description
Inkjet Printer
Uses either thermal bubble or piezoelectric technology
−
DLP//Projector
Mouse
−
−
4(a)
Operated by signals to cause a physical
movement Controls the movement of a
machine // by example
Uses thousands of tiny mirrors that can move very
quickly to create an image
−
Question
4
Name of
device
Actuator
Uses rolling ball / optical sensor / laser to
detect motion // by example
Movement echoed on screen // moves
curser/pointer (on screen)
Has scroll wheel / Buttons to allow data input
// by example
Answer
Six from
Max four from:
− Scanned using a barcode reader
− Shines (red) laser/light
− Light is reflected back // white lines reflect light // black lines reflect less
light
− Sensors/photoelectric cells detect the light
− Different reflections/bars give different binary/digital values // (pattern)
converted to binary/digital values
− Microprocessor interprets the data
− Uses check digit error checking
Max three from:
− Database stores data/barcodes/products/prices
− Barcode/value/key transmitted to database/system // Searches for
barcode/value/key in the database/system…
− … price is returned/found
© UCLES 2021
Marks
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Marks
6
0478/12
Question
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March 2021
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PUBLISHED
Answer
Marks
4(b)(i)
Max three from:
− Flash storage
− Uses transistors/controls gates/floating gates
− Can be NAND/NOR technology // Can use flip-flops
− Stores data by flashing it onto the chips/device
− Controlling/using the flow of electrons through/using
transistors/chips/gates
− The electric current reaches the control gate and flows through to the
floating gate to be stored
− When data is stored the transistor is converted from 1 to 0 / 0 to 1
3
4(b)(ii)
Max one from:
− Faster read/write operation
− Produces less heat // needs less cooling
− Less susceptible to interference/magnets
− Less power consumption
1
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PUBLISHED
0478/12
Question
Answer
5(a)
© UCLES 2021
Truth table
Marks
3
Logic gate
A
B
Output
0
0
1
0
1
1
1
0
1
1
1
0
A
B
Output
0
0
0
0
1
1
1
0
1
1
1
0
A
B
Output
0
0
1
0
1
0
1
0
0
1
1
0
NAND
[1]
XOR / Exclusive OR
[1]
NOR
[1]
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PUBLISHED
0478/12
Question
5(b)
Answer
One mark for each logic gates with correct inputs
−
−
−
−
−
Question
Marks
5
NOT A
NOT S
H AND NOT A
NOT A AND NOT S
Final OR
Answer
Marks
6(a)
Any four from:
− Monitors incoming and outgoing traffic
− Allows the setting of criteria/blacklist/whitelist/by example
− Blocks access to signals that do not meet
requirements/criteria/blacklist/whitelist …
− … sends signal to warn the user
− Restrict access to specific applications
− Blocks entry/exit by specific ports
4
6(b)
One mark for risk, two marks for description
6
© UCLES 2021
−
−
−
Phishing
Legitimate looking email sent to user
Clicking on link/attachment takes user to fake website
−
−
−
Pharming
Software is installed on user’s computer
Redirects (correct URL) to different/fraudulent website
−
−
−
−
Spyware (accept keylogger but do not award for MP3)
Software is installed on user’s computer
Records key strokes // keylogger
Transmits data to third part for analysis
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PUBLISHED
0478/12
Question
Answer
7(a)
Any two from:
− Makes use of words // close to human language
− Machine independent // portable
− Problem / logic focussed
− Needs to be translated/interpreter/compiled (to low-level for processing by
computer) // needs converting to machine code
2
7(b)
Four from
Max 2 for only giving compiler/interpreter features
4
7(c)
−
−
Both translate high level / source code to machine code
Both generate error diagnostics/messages // identify errors
−
−
Interpreter translates one line at a time // checks one line and then runs it
Compiler translates whole code in one go // checks all code and then runs
it
−
−
−
Interpreter stops when meets an error
…and then allows you to continue running from where you stopped //
correct errors in real-time
Compiler provides list of all errors
−
−
Interpreter does not produce an executable file
Compiler produces an executable file
Any five from:
− Free software is distributed with the source code
− …whereas shareware is not distributed with the source code
Marks
5
−
−
Free software allows modification of the application
…whereas shareware cannot be modified
−
Shareware normally allows a trial period for the end user // shareware has
limited features to start with
−
−
Free software is often available free of charge
…whereas shareware normally has a charge after trial period // shareware
has charge to access all features // shareware makes you sign-up/register
after trial period // shareware makes you sign-up/register to access all
features
7(d)
−
Claiming another person's work as your own
1
7(e)
−
To identify legal ownership // to claim ownership // protect intellectual
property
1
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Question
Answer
Marks
8(a)
−
−
Instructions and data stored in the same/main memory
Instructions fetched and executed in order / one after another / in
sequence
2
8(b)(i)
−
−
Holds the address …
… of next / current instruction
2
8(b)(ii)
Any two from:
− Carries / transfers control signals/instructions // carries/transfers
commands …
− … from CPU/CU to components // from devices to CPU/CU
− To synchronise the FE cycle
2
8(c)
Any two from:
− To identify that the processor's attention is required // to stop the current
process/task
− To allow multitasking
− To allow for efficient processing // prioritising actions
− To allow for efficient use of hardware
− To allow time-sensitive requests to be dealt with
− To avoid the need to poll devices
2
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Cambridge IGCSE™
* 3 0 5 1 9 9 1 3 9 5 *
COMPUTER SCIENCE
0478/11
May/June 2021
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 16 pages. Any blank pages are indicated.
DC (LK/SG) 202678/4
© UCLES 2021
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2
1
www.dynamicpapers.com
Benedict has a computer that is assigned an Internet Protocol (IP) address. The IP address is:
198.167.214.0
The IP address is represented as denary values.
(a) Convert the denary values 167 and 214 from the IP address to 8-bit binary.
167
214
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[2]
(b) Benedict’s computer is also assigned a Media Access Control (MAC) address.
(i)
Identify one similarity between an IP address and a MAC address.
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
Identify two differences between an IP address and a MAC address.
Difference 1 .......................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
Difference 2 .......................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[2]
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2
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Julia inputs personal data into her computer.
She stores three copies of the data using a hard disk drive (HDD), a solid state drive (SSD) and a
USB flash memory drive.
(a) Identify three devices Julia can use to input personal data into her computer.
Device 1 ....................................................................................................................................
Device 2 ....................................................................................................................................
Device 3 ....................................................................................................................................
[3]
(b) Six statements are shown about HDDs, SSDs and USB flash memory drives.
Tick (✓) to show which statements apply to each type of storage. Some statements can apply
to more than one type of storage.
Statement
HDD
(✓)
SSD
(✓)
USB flash
memory
drive
(✓)
it has no moving parts
it is non-volatile
it can use NAND gates to store data
it uses magnetic properties to store data
it has the smallest physical size
it has the slowest read/write speeds
[6]
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4
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(c) Julia uses a USB connection to transfer data onto her USB flash memory drive.
(i)
One benefit of using a USB connection is that it is a universal connection.
State two other benefits of using a USB connection.
Benefit 1 ............................................................................................................................
...........................................................................................................................................
Benefit 2 ............................................................................................................................
...........................................................................................................................................
[2]
(ii)
Identify the type of data transmission used in a USB connection.
..................................................................................................................................... [1]
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3
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A firewall can be used to help keep the data secure that is stored on a computer.
(a) The given paragraph describes how the firewall operates to help keep the data secure.
Complete the paragraph using the most appropriate terms from the given list. Not all of the
terms on the list need to be used.
•
•
•
•
•
•
•
•
•
•
•
•
Accept
Criteria
Hacking
Input
Network
Outgoing
Output
Processor
Reject
Software
Store
Storage
A firewall can be ............................................ or hardware based. It monitors traffic between
the computer and the ............................................ The user sets ............................................
for the traffic. The firewall will .............................................. or ............................................
the traffic based on this. It can help prevent ............................................ and malicious
software that could be a threat to the security of the data.
[6]
(b) Identify three other methods that could be used to keep the data secure.
Method 1 ...................................................................................................................................
Method 2 ...................................................................................................................................
Method 3 ...................................................................................................................................
[3]
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0478/11/M/J/21
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6
4
www.dynamicpapers.com
Two internet risks are phishing and pharming.
Describe what is meant by phishing and pharming.
Phishing ...........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
Pharming ..........................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
[6]
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7
5
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Jamelia has a greenhouse that she uses to grow fruit and vegetables. She needs to make sure
the temperature in the greenhouse stays between 25 °C and 30 °C (inclusive).
A system that has a temperature sensor and a microprocessor is used to maintain the temperature
in the greenhouse. The system will:
•
•
open a window and turn a heater off if it gets too hot
close a window and turn a heater on if it gets too cold.
Describe how the system uses the temperature sensor and the microprocessor to maintain the
temperature in the greenhouse.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
.................................................................................................................................................... [8]
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0478/11/M/J/21
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8
6
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Consider the logic statement:
X = (((A AND B) OR (C AND NOT B)) XOR NOT C)
(a) Draw a logic circuit to represent the given logic statement.
Do not attempt to simplify the statement. All logic gates must have a maximum of two inputs.
A
B
X
C
[6]
© UCLES 2021
0478/11/M/J/21
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9
(b) Consider the completed truth table for the given logic statement.
Row
number
A
B
C
1
0
0
0
0
2
0
0
1
1
3
0
1
0
0
4
0
1
1
1
5
1
0
0
0
6
1
0
1
1
7
1
1
0
0
8
1
1
1
1
Working space
X
There are four errors in the truth table in the output (X) column.
Identify the four incorrect outputs.
Write the row number to identify each incorrect output.
Row ........................
Row ........................
Row ........................
Row ........................
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7
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A music company has a website that allows users to stream music. The music is stored in sound
files.
(a) The sound files are compressed using lossless compression.
(i)
Describe how the sound files are compressed using lossless compression.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(ii)
State one reason why the music company would compress the sound files using
lossless, rather than lossy, compression.
...........................................................................................................................................
..................................................................................................................................... [1]
(iii)
Give one benefit, to the user, of the music company compressing the sound files.
...........................................................................................................................................
..................................................................................................................................... [1]
(iv)
Give one drawback of the music company using lossless, rather than lossy, compression
for the sound files.
...........................................................................................................................................
..................................................................................................................................... [2]
© UCLES 2021
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(b) Describe how the web pages for the website are requested and displayed on a user’s
computer.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
(c) The web server that hosts the website suffers a denial of service (DoS) attack.
Explain why this will prevent users from accessing the website.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
© UCLES 2021
0478/11/M/J/21
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12
8
Four 7-bit binary values are transmitted from one computer to another. A parity bit is added to
each binary value creating 8-bit binary values. All the binary values are transmitted and received
correctly.
(a) Identify whether each 8-bit binary value has been sent using odd or even parity by writing odd
or even in the type of parity column.
8-bit binary value
Type of parity
01100100
10010001
00000011
10110010
[4]
(b) An error may not be detected when using a parity check.
Identify why an error may not be detected.
...................................................................................................................................................
............................................................................................................................................. [1]
(c) The data is sent using parallel half-duplex data transmission.
(i)
Describe how data is sent using parallel half-duplex data transmission.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(ii)
State two drawbacks of using parallel data transmission.
Drawback 1 .......................................................................................................................
...........................................................................................................................................
Drawback 2 .......................................................................................................................
...........................................................................................................................................
[2]
© UCLES 2021
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2021
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Cambridge IGCSE™
COMPUTER SCIENCE
0478/11
Paper 1
May/June 2021
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2021 series for most Cambridge
IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.
This document consists of 8 printed pages.
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Generic Marking Principles
These general marking principles must be applied by all examiners when marking candidate answers.
They should be applied alongside the specific content of the mark scheme or generic level descriptors
for a question. Each question paper and mark scheme will also comply with these marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit
is given for valid answers which go beyond the scope of the syllabus and mark scheme,
referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these
features are specifically assessed by the question as indicated by the mark scheme. The
meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently, e.g. in situations where candidates have not followed
instructions or in the application of generic level descriptors.
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question
(however; the use of the full mark range may be limited according to the quality of the candidate
responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should
not be awarded with grade thresholds or grade descriptors in mind.
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May/June 2021
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Please note the following further points:
The words in bold in the mark scheme are important text that needs to be present, or some notion
of it needs to be present. It does not have to be the exact word, but something close to the
meaning.
If a word is underlined, this exact word must be present.
A single forward slash means this is an alternative word. A double forward slash means that this is
an alternative mark point.
Ellipsis (…) on the end of one-mark point and the start of the next means that the candidate cannot
get the second mark point without being awarded the first one. If a MP has ellipsis at the beginning,
but there is no ellipsis on the MP before it, then this is just a follow-on sentence and can be
awarded without the previous mark point.
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PUBLISHED
0478/11
Question
1(a)
Answer
One mark per each correct register.
Marks
2
1
0
1
0
0
1
1
1
1
1
0
1
0
1
1
0
1(b)(i)
Any one from:
− Both addresses can be used to identify a computer/device
− Both are unique
− Both can be represented as hexadecimal
− Both addresses do not change if IP address is static
1
1(b)(ii)
Any two from:
− An IP address is assigned by the network/router/ISP, A MAC address is
assigned by the manufacturer
− An IP address can be changed (if dynamic), MAC address cannot be
changed
− IP address has 4/8 groups of values, MAC address has 6 groups/pairs of
values
− IP address is 32-bit/128-bit, MAC address is 48-bit
− IP address does not contain serial number/manufacturer number, MAC
address does
− IP(v4) address is denary and MAC address is hexadecimal
2
Question
Answer
2(a)
© UCLES 2021
Any three from:
− Keyboard
− Mouse
− Microphone
− Keypad
− Touchscreen
− Touchpad
Marks
3
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PUBLISHED
0478/11
Question
2(b)
Answer
Marks
One mark for each correct row.
6
Statement
HDD
()
it has no moving parts

it is non-volatile
it can use NAND gates to store data
it uses magnetic properties to store data
SSD
()
USB flash
memory
drive
()








it has the smallest physical size
it has the slowest read/write speeds

2(c)(i)
Any two from:
− It cannot be inserted incorrectly
− Supports different transmission speeds
− High speed transmission
− Automatically detected (not connected) // automatically downloads
drivers
− Powers the device (for data transfer)
− Backward compatible
2
2(c)(ii)
−
1
Question
3(a)
© UCLES 2021
Serial
Answer
One mark per each correct term in the correct order.
− Software
− Network
− Criteria
− Accept // reject
− Reject // accept
− Hacking
Page 5 of 8
Marks
6
Cambridge IGCSE – Mark Scheme
May/June 2021
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PUBLISHED
0478/11
Question
3(b)
Answer
Any three from:
− Password
− Biometrics (device)
− Encryption
− Physical methods (e.g. locks)
− Two-factor authentication // Two-step verification
− Anti-viruses
Question
4
Answer
Marks
3
Marks
6
Any six from:
Phishing
− Legitimate looking email sent to user
− encourages user to click a link that directs user to a fake website
− User encouraged to enter personal details into a fake website // designed
to obtain personal details from a user
Pharming
− Malicious code/malware is downloaded/installed // software downloaded
without users' knowledge
− … that re-directs user to fake website (when legitimate URL entered)
− User encouraged to enter personal details into a fake website // designed
to obtain personal details from a user
Question
5
© UCLES 2021
Answer
Eight from:
− Sensor send data/readings/signal to microprocessor
− Data is converted from analogue to digital (using ADC)
− Microprocessor compares/checks data to stored values/range of values
…
− … If data is greater than 30 / above the range microprocessor sends
signal to open window and to turn heater off
− … If data is below 25 the microprocessor sends signal to turn on heater
and to close window
− … If data is between 25 and 30 / within the range no action taken
− Actuator is used to operate heater/window
− Whole process is continuous
Page 6 of 8
Marks
8
Cambridge IGCSE – Mark Scheme
May/June 2021
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PUBLISHED
0478/11
Question
Answer
Marks
6(a)
One mark per each correct logic gate, with correct input:
6
6(b)
−
−
−
−
4
Question
7(a)(i)
Row 1
Row 3
Row 4
Row 5
Answer
Four from:
− (Compression) algorithm is used
− No data will be removed // original file can be restored
− Example of type of algorithm that would be used e.g. RLE
− Repeated patterns in the music are identified
− … and indexed
Marks
4
NOTE: If another lossless method is described, marks can be awarded.
7(a)(ii)
Any one from:
− To provide the highest quality of music file (that compression will allow)
− The user is able to listen to the original sound file
− No loss of quality for the sound file provided
1
7(a)(iii)
Any one from:
− Allow for quicker streaming speed
− Would not require as much bandwidth (to stream)
− Does not need as much RAM
− Smoother listening experience // less lag
− Will not use as much of data allowance
1
© UCLES 2021
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May/June 2021
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PUBLISHED
0478/11
Question
7(a)(iv)
Answer
Marks
Two from:
− Streaming speed may be slower
− … and may affect listening experience // buffering may occur
− User may need more bandwidth to stream
− … that could be more expensive
− It would be a larger file size
− … so may take longer to upload
− … so will take up more storage space …
− … on webserver
2
7(b)
Any four from:
− Browser sends URL to DNS
− … using HTTP/HTTPS
− IP address is found on DNS
− DNS returns IP address to the browser
− Browser sends request to web server/IP address
− Web server sends web pages back to browser
− Browser interprets/renders the HTML (to display web pages)
− Security certificates exchanged
4
7(c)
Two from:
− Web server has been flooded with traffic // web server has been sent
many requests at once
− … so, server is brought to a halt / crashes
2
Question
Answer
Marks
8(a)
−
−
−
−
8(b)
Any one from:
− there is a transposition of bits
− it does not check the order of the bits (just the sum of 1s/0s)
− even number of bits change
− incorrect bits still add up to correct parity
1
8(c)(i)
Four from:
− Multiple bits are sent at the same time
− Uses multiple wires
− Data is sent in both directions …
− … but only one direction at a time
4
8(c)(ii)
Any two from:
− Bits may arrive skewed
− More expensive to setup/manufacture/purchase cable
− Limited distance
− More prone to interference/error
2
© UCLES 2021
4
Odd
Odd
Even
Even
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Cambridge IGCSE™
* 1 8 7 5 9 9 1 1 3 6 *
COMPUTER SCIENCE
0478/12
May/June 2021
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Any blank pages are indicated.
DC (DH/SG) 202677/4
© UCLES 2021
[Turn over
2
1
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A denary value can be converted into hexadecimal and binary.
(a) Complete the table to show the hexadecimal and 8-bit binary values of the given denary
values.
Denary
Hexadecimal
8-bit binary
49
123
200
[6]
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
(b) Give two benefits, to users, of converting binary values to hexadecimal.
Benefit 1 ....................................................................................................................................
...................................................................................................................................................
Benefit 2 ....................................................................................................................................
...................................................................................................................................................
[2]
(c) Hexadecimal is used to represent Hypertext Markup Language (HTML) colour codes in
computer science.
Identify three other ways that hexadecimal is used in computer science.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
© UCLES 2021
0478/12/M/J/21
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3
2
Data storage can be magnetic, solid state or optical.
(a) Six statements are given about data storage.
Tick (3) to show if the statement applies to magnetic, solid state or optical storage. Some
statements may apply to more than one type of storage.
Magnetic
(3)
Statement
Solid state
(3)
Optical
(3)
no moving parts are used to store data
pits and lands are used to store data
data is stored on platters
flash memory is used to store data
parts are rotated to store data
data can be stored permanently
[6]
(b) (i)
Give one example of magnetic storage.
..................................................................................................................................... [1]
(ii)
Give one example of optical storage.
..................................................................................................................................... [1]
(iii)
Identify which type of storage would be the most suitable for use in a web server and
justify your choice.
Type of storage ..................................................................................................................
Justification ........................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
(c) Describe the operation of USB flash memory and how it stores data.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
© UCLES 2021
0478/12/M/J/21
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Consider the logic statement:
X = ((((NOT A AND B) OR C) AND B) NOR (B OR C))
(a) Draw a logic circuit to represent the given logic statement.
Do not attempt to simplify the statement. All logic gates must have a maximum of two inputs.
A
B
X
C
[6]
© UCLES 2021
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5
www.dynamicpapers.com
(b) Consider the completed truth table for the given logic statement.
Row
number
A
B
C
1
0
0
0
1
2
0
0
1
1
3
0
1
0
1
4
0
1
1
0
5
1
0
0
1
6
1
0
1
0
7
1
1
0
1
8
1
1
1
1
Working space
X
There are four errors in the truth table in the output (X) column.
Identify the four incorrect outputs.
Write the row number to identify each incorrect output.
Row .......................
Row .......................
Row .......................
Row .......................
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[4]
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6
4
Three types of Internet security risk are virus, spyware and denial of service (DoS) attack.
(a) Six statements are given about Internet security risks.
Tick (3) to show whether the statement applies to virus, spyware or denial of service. Some
statements may apply to more than one Internet security risk.
Statement
Virus
(3)
Spyware
(3)
Denial of
service
(3)
captures all data entered using a keyboard
can be installed onto a web server
prevents access to a website
is malicious code on a computer
is self-replicating
damages the files on a user’s hard drive
[6]
(b) Identify three other types of Internet security risks.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
(c) Some Internet security risks can maliciously damage data. Data can also be damaged
accidentally.
State three ways that data could be accidentally damaged.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
© UCLES 2021
0478/12/M/J/21
7
5
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A security light system is used by a factory. The light only comes on when it is dark and when
movement is detected. The light will stay on for 1 minute before switching off.
Sensors and a microprocessor are used to control the security light system.
(a) Identify two sensors that would be used in the security light system.
Sensor 1 ...................................................................................................................................
Sensor 2 ...................................................................................................................................
[2]
(b) Describe how the sensors and the microprocessor control the security light system.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [8]
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0478/12/M/J/21
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6
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Cookies can be used to store a user’s personal data and online browsing habits.
(a) A cookie could be used to automatically enter a user’s payment details when the user makes
a purchase online.
Describe how cookies can be used to store and automatically enter a user’s payment details.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) Explain why a user may be concerned about their personal data and online browsing habits
being stored in cookies.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
© UCLES 2021
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7
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Jolene uses HTML to create a website. She separates the HTML into structure and presentation.
(a) (i)
Give one example of HTML structure.
..................................................................................................................................... [1]
(ii)
Give two examples of HTML presentation.
1 ........................................................................................................................................
2 ........................................................................................................................................
[2]
(b) Explain why Jolene separates the HTML into structure and presentation.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [2]
8
A keyboard is a type of input device that can be used to enter data into a computer.
Complete the paragraph that describes one method of operation for a keyboard, using the most
appropriate terms from the given list. Not all terms in the list need to be used.
•
•
•
•
•
•
•
•
•
•
•
•
Binary
Breaks
Calculated
Character
Circuit
Current
Information
Network
Press
Processor
Signal
Switch
A keyboard has a key matrix underneath the keys. When a key is pressed, it presses a
............................................. that completes a ............................................. . This allows
............................................. to flow. The location of the key pressed is
............................................. . The location of the key pressed is compared to a
............................................. map to find the ............................................. value for the key that
has been pressed.
© UCLES 2021
[6]
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11
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2021
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Cambridge IGCSE™
COMPUTER SCIENCE
0478/12
Paper 1
May/June 2021
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2021 series for most Cambridge
IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.
This document consists of 8 printed pages.
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Cambridge IGCSE – Mark Scheme
May/June 2021
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PUBLISHED
Generic Marking Principles
These general marking principles must be applied by all examiners when marking candidate answers.
They should be applied alongside the specific content of the mark scheme or generic level descriptors
for a question. Each question paper and mark scheme will also comply with these marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit
is given for valid answers which go beyond the scope of the syllabus and mark scheme,
referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these
features are specifically assessed by the question as indicated by the mark scheme. The
meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently, e.g. in situations where candidates have not followed
instructions or in the application of generic level descriptors.
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question
(however; the use of the full mark range may be limited according to the quality of the candidate
responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should
not be awarded with grade thresholds or grade descriptors in mind.
© UCLES 2021
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Cambridge IGCSE – Mark Scheme
May/June 2021
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PUBLISHED
Please note the following further points:
The words in bold in the mark scheme are important text that needs to be present, or some notion
of it needs to be present. It does not have to be the exact word, but something close to the
meaning.
If a word is underlined, this exact word must be present.
A single forward slash means this is an alternative word. A double forward slash means that this is
an alternative mark point.
Ellipsis (…) on the end of one-mark point and the start of the next means that the candidate cannot
get the second mark point without being awarded the first one. If a MP has ellipsis at the beginning,
but there is no ellipsis on the MP before it, then this is just a follow-on sentence and can be
awarded without the previous mark point.
© UCLES 2021
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Cambridge IGCSE – Mark Scheme
May/June 2021
www.dynamicpapers.com
PUBLISHED
0478/12
Question
1(a)
Answer
Marks
One mark per each correct binary value.
One mark per each correct hex value.
Denary
Hexadecimal
8-bit binary
49
31
00110001
123
7B
01111011
200
C8
11001000
6
1(b)
Any two from:
− Easier/quicker to read/write/understand
− Easier/quicker to identify errors/debug
− Takes up less screen/display space
− Less chance of making an error
2
1(c)
Any three from:
− MAC address
− URL
− Assembly language
− Error codes // error messages
− IP addresses
− Locations in memory
− Memory dumps
3
Question
2(a)
Answer
Marks
One mark per each correct row.
6
Magnetic
()
Statement
Solid
state
()

no moving parts are used to store data

pits and lands are used to store data

data is stored on platters

flash memory is used to store data
2(b)(i)
© UCLES 2021
Optical
()
parts are rotated to store data

data can be stored permanently

Any one from:
− Hard disk drive // HDD
− Magnetic tape



1
Page 4 of 8
Cambridge IGCSE – Mark Scheme
May/June 2021
www.dynamicpapers.com
PUBLISHED
0478/12
Question
Answer
Marks
2(b)(ii)
Any one from:
− CD
− DVD
− Blu-ray disk
1
2(b)(iii)
One for type of storage, two for matching justification from:
− Magnetic // HDD
− (Web server) is likely to receive many requests a day
− (Web server) will likely need to store a lot of data and magnetic is high
capacity
− Magnetic is cheaper to buy for storage per unit than solid state
− Magnetic is capable of more of read/write requests over time // has more
longevity // SSD has more limited number of read/write requests (before
it is no longer usable)
− No requirement for it to be portable, so moving parts does not matter
3
−
−
−
−
−
−
Solid-state // SSD
(Web server) is likely to receive many requests a day
(Web server) will likely need to store a lot of data and solid-state is high
capacity
Solid-state is more energy efficient
Solid-state runs cooler so will not overheat
Solid state has faster read/write speeds to handle volume of traffic
2(c)
Any three from:
− Data is flashed onto (silicon) chips
− Uses NAND/NOR technology // can use flip-flops
− Uses transistors/control gates/floating gates …
− … to control the flow of electrons
− It is a type of EEPROM technology
− When data is stored the transistor is converted from 1 to 0 / 0 to 1
− Writes (and reads) sequentially
3
3(a)
One mark for each correct logic gate with correct input.
6
© UCLES 2021
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May/June 2021
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PUBLISHED
0478/12
Question
3(b)
Answer
One mark per each correct row.
− Row 2
− Row 3
− Row 7
− Row 8
4
Question
4(a)
Marks
Answer
Marks
One mark per each correct row.
6
Virus
()
Statement
Denial of
service
()

captures all data entered using a keyboard
can be installed onto a web server
Spyware
()



prevents access to a website
is malicious code on a computer

is self-replicating

damages the files on a user’s hard drive


4(b)
Any three from:
− Phishing
− Pharming
− Hacking // cracking
3
4(c)
Any three from:
− Human error
− Power failure/surge
− Hardware failure
− Software failure
− Fire
− Flood
3
5(a)
−
−
2
© UCLES 2021
Light sensor
Motion sensor // infra-red sensor
Page 6 of 8
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May/June 2021
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PUBLISHED
0478/12
Question
Answer
Marks
5(b)
Eight from:
− Sensors send data to microprocessor
− Data is converted to digital (using ADC)
− Microprocessor compares data to stored value(s) …
− … if one value or neither values are within range/out of range/match no
action is taken
− … If both values are out of range/in range/match microprocessor sends
signal to switch light on …
− … 1-minute timer is started
− Actuator used to switch on/off light
− When timer reaches 1 minute, microprocessor sends signal to switch
light off
− Whole process is continuous
8
6(a)
Any three from:
− Webserver sends (cookie) file to user’s browser
− User’s payment details stored in encrypted text file // data is encrypted to
be stored
− Cookie file is stored by browser/on user’s HDD/SSD
− When user revisits website, webserver requests cookie file // webserver
can access the data stored in the cookie file (to automatically enter
details)
− … and browser sends cookie file back to webserver (to automatically
enter the details)
3
6(b)
Four from:
− User does not see what information is stored // might collect data that
user does not know about …
− … so, user may feel their privacy is affected
4
−
−
A profile could be built about the user …
… that could expose a user’s identity // lead to identity theft
−
Sensitive information stored in cookies could be intercepted in
transmission …
Other websites could gain access to the cookies stored on a user’s
computer …
Computer could be hacked to obtain data stored in cookies …
… so, payment information could be stolen and used by a third party
−
−
−
Question
7(a)(i)
Answer
Any one from:
− Placement of text/image
− Margins
− Line break
− Padding
1
NOTE: Any relevant example of structure can be awarded
© UCLES 2021
Marks
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May/June 2021
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PUBLISHED
Question
7(a)(ii)
Answer
Any two from:
− Font colour
− Font style
− Font size
− Background colour
− Image size
− Border properties
Marks
2
NOTE: Any relevant example of presentation can be awarded
7(b)
8
© UCLES 2021
Any two from:
− Can easily change/edit the style of the webpage
− So, CSS can be used to create a template/style sheet
− Can add new content and apply the same style easily
− Can re-use the presentation/style for other websites
2
One mark for each correct term in the correct order
− Switch
− Circuit
− Current
− Calculated
− Character
− Binary
6
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Cambridge IGCSE™
* 3 0 8 8 7 7 7 2 2 4 *
COMPUTER SCIENCE
0478/13
May/June 2021
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 16 pages. Any blank pages are indicated.
DC (DH/SG) 202681/5
© UCLES 2021
[Turn over
2
1
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Greta has a computer that she uses for schoolwork and leisure.
(a) The computer has the Media Access Control (MAC) address:
00:A0:C9:14:C8:29
(i)
Tick (3) to show whether the MAC address is initially assigned to the computer by the
network, the manufacturer or the user.
Tick (3)
Network
Manufacturer
User
[1]
(ii)
The values in the MAC address are hexadecimal values.
Convert the three given hexadecimal values into 8-bit binary.
14 ......................................................................................................................................
A0 ......................................................................................................................................
C9 ......................................................................................................................................
[3]
Working space
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
(iii)
Convert the two given hexadecimal values into denary.
29 ......................................................................................................................................
C8 ......................................................................................................................................
[2]
Working space
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
© UCLES 2021
0478/13/M/J/21
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(b) Greta stores data on several off-line storage devices, including an external hard disk drive
(HDD), a USB flash memory drive and a compact disc (CD).
(i)
Identify the type of storage for each device.
External HDD ....................................................................................................................
USB flash memory drive ...................................................................................................
CD .....................................................................................................................................
[3]
(ii)
Describe the operation of a HDD and how it stores data.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
© UCLES 2021
0478/13/M/J/21
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4
2
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Jolene displays videos on her website. She uses lossy compression to reduce the file size of the
videos.
(a) Describe how lossy compression reduces the file size of the videos.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) State two reasons why Jolene would use lossy rather than lossless compression for the
videos.
Reason 1 ..................................................................................................................................
...................................................................................................................................................
Reason 2 ..................................................................................................................................
...................................................................................................................................................
[2]
© UCLES 2021
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5
3
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An optical mouse is a type of input device that can be used to input data into a computer system.
(a) Complete the paragraph about the operation of an optical mouse, using the most appropriate
terms from the given list. Not all terms need to be used.
•
•
•
•
•
•
•
•
•
•
•
•
Ball
Battery
LCD
LED
Lens
Magnifies
Matrix
Microswitch
Photoelectric
Photographic
Reduces
USB
An optical mouse shines an ............................................ from the bottom of the mouse onto a
surface. Light bounces straight back from the surface into a ............................................ cell.
This has a ............................................ that ............................................ the reflected light to
allow detection of smaller movements. When a button on the mouse is clicked, a
............................................ is pressed. A ............................................ connection is used to
carry the data to the computer.
[6]
(b) Identify two other input devices that can be used to enter data into a computer.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
© UCLES 2021
0478/13/M/J/21
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4
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Spencer finds out that his online music account has been accessed by an unauthorised person.
He believes his personal details for the account were obtained using phishing.
(a) Explain how the personal details could have been obtained using phishing.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [3]
(b) Give two other Internet security risks that could have been used to obtain the personal
details.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
© UCLES 2021
0478/13/M/J/21
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7
5
Six statements are given about programming languages.
Tick (3) to show whether each statement applies to high-level language, assembly language or
machine code. Some statements may apply to more than one type of programming language.
High-level
language
(3)
Statement
Assembly
language
(3)
Machine
code
(3)
it requires a translator to be processed by a
computer
it is an example of low-level language
it uses mnemonics
it uses English-like statements
it can be used to directly manipulate hardware in
the computer
it is portable
[6]
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8
6
Four 7-bit binary values are transmitted from one computer to another. A parity bit is added to
each binary value creating 8-bit binary values. All the binary values are transmitted and received
correctly.
(a) Identify whether each 8-bit binary value has been sent using odd or even parity by writing odd
or even in the type of parity column.
8-bit binary value
Type of parity
01111100
10010000
10011001
00101001
[4]
(b) The 8-bit binary value 10110001 is transmitted and received as 10110010
A parity check does not identify any errors in the binary value received.
State why the parity check does not identify any errors.
...................................................................................................................................................
............................................................................................................................................. [1]
(c) The data is sent using serial duplex data transmission.
(i)
Describe how data is sent using serial duplex data transmission.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [4]
(ii)
State one drawback of using serial data transmission, rather than parallel data
transmission.
...........................................................................................................................................
..................................................................................................................................... [1]
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Marco uses his computer for work. The data he uses on a daily basis is valuable to his business.
Marco is concerned about his data being accidentally damaged. Human error, such as incorrectly
removing external storage devices, is one way that the data can be accidentally damaged.
(a) Identify two other ways that data can be accidentally damaged.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
(b) Removing storage devices correctly from the computer can help prevent data being
accidentally damaged.
Give two other ways that accidental damage to data can be prevented.
1 ................................................................................................................................................
...................................................................................................................................................
2 ................................................................................................................................................
...................................................................................................................................................
[2]
© UCLES 2021
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Consider the following logic circuit:
A
X
B
C
(a) Two NOT gates are used in the given logic circuit.
Identify three other logic gates that are used in the given logic circuit.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]
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(b) Consider the completed truth table for the given logic circuit.
Row
number
A
B
C
1
0
0
0
0
2
0
0
1
1
3
0
1
0
0
4
0
1
1
0
5
1
0
0
1
6
1
0
1
1
7
1
1
0
0
8
1
1
1
1
Working space
X
There are four errors in the truth table in the output (X) column.
Identify the four incorrect outputs.
Write the row number to identify each incorrect output.
Row .......................
Row .......................
Row .......................
Row .......................
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[4]
0478/13/M/J/21
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9
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An underground car park has a system that checks the height of vehicles. A vehicle can be no
higher than 1.8 metres to enter the car park.
The system also counts the number of vehicles that have entered the car park, so that it can
display how many parking spaces are still available.
Each parking space has a red and a green light above it. If a car is parked in the parking space
only the red light is on, otherwise only the green light is on.
Sensors and a microprocessor are used to control the system.
(a) Complete the table to identify a suitable sensor for each part of the system.
Task
Sensor
check if a vehicle is too high
count the vehicles entering the car park
check if a vehicle is parked in a parking space
[3]
(b) Describe how the sensor and the microprocessor are used to display the red or green light
above the parking space.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
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10 Several components are involved in processing an instruction in a Von Neumann model for a
computer system.
Three of these components are the arithmetic logic unit (ALU), control unit (CU) and random
access memory (RAM).
(a) Six statements are given about the components.
Tick (3) to show if each statement applies to the ALU, CU or the RAM. Some statements may
apply to more than one component.
ALU
(3)
Statement
CU
(3)
RAM
(3)
stores data and instructions before they enter the central
processing unit (CPU)
contains a register called the accumulator
manages the transmission of data and instructions to the
correct components
contained within the CPU
uses the data bus to send data into or out of the CPU
carries out calculations on data
[6]
(b) The accumulator is a register that is part of the Von Neumann model.
Give two other registers that are part of the Von Neumann model.
1 ................................................................................................................................................
2 ................................................................................................................................................
[2]
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
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Cambridge IGCSE™
COMPUTER SCIENCE
0478/13
Paper 1
May/June 2021
MARK SCHEME
Maximum Mark: 75
Published
This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.
Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.
Cambridge International will not enter into discussions about these mark schemes.
Cambridge International is publishing the mark schemes for the May/June 2021 series for most Cambridge
IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.
This document consists of 8 printed pages.
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Cambridge IGCSE – Mark Scheme
May/June 2021
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PUBLISHED
Generic Marking Principles
These general marking principles must be applied by all examiners when marking candidate answers.
They should be applied alongside the specific content of the mark scheme or generic level descriptors
for a question. Each question paper and mark scheme will also comply with these marking principles.
GENERIC MARKING PRINCIPLE 1:
Marks must be awarded in line with:
•
•
•
the specific content of the mark scheme or the generic level descriptors for the question
the specific skills defined in the mark scheme or in the generic level descriptors for the question
the standard of response required by a candidate as exemplified by the standardisation scripts.
GENERIC MARKING PRINCIPLE 2:
Marks awarded are always whole marks (not half marks, or other fractions).
GENERIC MARKING PRINCIPLE 3:
Marks must be awarded positively:
•
•
•
•
•
marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit
is given for valid answers which go beyond the scope of the syllabus and mark scheme,
referring to your Team Leader as appropriate
marks are awarded when candidates clearly demonstrate what they know and can do
marks are not deducted for errors
marks are not deducted for omissions
answers should only be judged on the quality of spelling, punctuation and grammar when these
features are specifically assessed by the question as indicated by the mark scheme. The
meaning, however, should be unambiguous.
GENERIC MARKING PRINCIPLE 4:
Rules must be applied consistently, e.g. in situations where candidates have not followed
instructions or in the application of generic level descriptors.
GENERIC MARKING PRINCIPLE 5:
Marks should be awarded using the full range of marks defined in the mark scheme for the question
(however; the use of the full mark range may be limited according to the quality of the candidate
responses seen).
GENERIC MARKING PRINCIPLE 6:
Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should
not be awarded with grade thresholds or grade descriptors in mind.
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Please note the following further points:
The words in bold in the mark scheme are important text that needs to be present, or some notion
of it needs to be present. It does not have to be the exact word, but something close to the
meaning.
If a word is underlined, this exact word must be present.
A single forward slash means this is an alternative word. A double forward slash means that this is
an alternative mark point.
Ellipsis (…) on the end of one-mark point and the start of the next means that the candidate cannot
get the second mark point without being awarded the first one. If a MP has ellipsis at the beginning,
but there is no ellipsis on the MP before it, then this is just a follow-on sentence and can be
awarded without the previous mark point.
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May/June 2021
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PUBLISHED
0478/13
Question
Answer
1(a)(i)
−
1(a)(ii)
One mark per each correct binary value.
−
−
−
1a(iii)
1
manufacturer
3
00010100
10100000
11001001
One mark per each correct denary value.
−
−
41
200
1(b)(i)
−
−
−
Magnetic
Solid state
Optical
1(b)(ii)
Any four from:
− It has platters
− Platters/disk divided into tracks
− Platter/disk is spun
− Has a read/write arm that moves across storage media
− Read/writes data using electromagnets
− Uses magnetic fields to control magnetic dots of data
− Magnetic field determines binary value
Question
Marks
2
3
Answer
4
Marks
2(a)
Any three from:
− A compression algorithm is used
− Redundant data is removed
− Reduce colour depth
− Reduce image resolution
− Reduce sample rate
− Reduce sample resolution
− Reduce frame rate
− Use perceptual music shaping
− Data is permanently removed
3
2(b)
Any two from:
− Lossy decreases the file size more
− Take up less storage space on webserver/users' computer
− Quicker to upload/download
− May not need to be high quality
− Website will load faster for users
− Less lag/buffering when watching
− Takes up less bandwidth to download/upload
− Uses less data allowance
2
© UCLES 2021
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PUBLISHED
0478/13
Question
Answer
Marks
3(a)
One mark per each correct term, in the correct place.
− LED
− Photoelectric
− Lens
− Magnifies
− Microswitch
− USB
6
3(b)
Any two from:
− Keyboard
− Microphone
− 2D/3D Scanner
− Sensor
− Touchscreen
− Keypad
− Webcam
− Joystick
2
Question
Answer
4(a)
−
−
−
4(b)
Any two from:
− Pharming
− Spyware
− Hacking/cracking
© UCLES 2021
Marks
Legitimate looking/fake email sent to user
… that contains a link to a fake website
User clicks link and enters personal details (into fake website)
3
2
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PUBLISHED
0478/13
Question
5
Answer
Marks
One mark per each correct row
Statement
6
High-level
language
()
Assembly
language
()


It requires a translator to be
processed by a computer
It is an example of low-level
language

It uses mnemonics

It uses English-like
statements


It can be used to directly
manipulate hardware in the
computer



It is portable
Question
Machine
code
()
Answer
Marks
6(a)
−
−
−
−
6(b)
Any one from:
− There is a transposition of bits
− Bits still add up to correct parity
1
6(c)(i)
−
−
−
−
4
6(c)(ii)
Any one from:
− Data transmission can be slower (than parallel)
− Additional data may need to be sent
© UCLES 2021
4
Odd
Even
Even
Odd
Data is sent one bit at a time
Data is sent using a single wire
Data is sent in both direction …
… at the same time
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1
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Question
Answer
Marks
7(a)
Any two from:
− Hardware failure
− Software failure
− Power failure/surge
− Fire
− Flood
− Natural disaster
2
7(b)
Any two from:
− Use verification methods before deleting files
− Keep data in a fireproof box
− Do not drink liquids near a computer
− Use surge protection // UPS
− Correct shutdown procedures
− Access rights
− Back data up
2
Question
Answer
Marks
8(a)
−
−
−
AND
NOR
XOR
3
8(b)
−
−
−
−
Row 1
Row 4
Row 7
Row 8
4
Question
9(a)
Answer
One mark per each correct sensor
Task
© UCLES 2021
Marks
3
Sensor
Check if a vehicle is too high
Infrared/light
Count the vehicles entering the car
park
Magnetic field // pressure
Check if a vehicle is parked in a
parking space
Pressure // magnetic field //
infrared/light
Page 7 of 8
Cambridge IGCSE – Mark Scheme
May/June 2021
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PUBLISHED
0478/13
Question
9(b)
Answer
Six from:
− Sensor sends data to microprocessor
− Data is converted from analogue to digital (using ADC)
− Data is compared to stored value …
− … If data is greater than stored value microprocessor sends signal to
turn red light on and the green light off
− … If data is less than stored value microprocessor sends signal to turn
green light on the red light off
− … If data still within range, no action taken/existing light remains on
− Lights turned on/off using actuator
− Process is continuous
Question
10(a)
Marks
Answer
Marks
One mark per each correct row
6
ALU
()
Statement
CU
()
Stores data and instructions before
they enter the central processing unit
(CPU)
Contains a register called the
accumulator



Contained within the CPU
Uses the data bus to send data into or
out of the CPU
Carries out calculations on data
© UCLES 2021
RAM
()

Manages the transmission of data and
instructions to the correct components
10(b)
6
Any two from:
− MAR
− MDR // MBR
− PC
− CIR // IR
()



2
Page 8 of 8
Cambridge IGCSE™
* 0 0 6 3 3 2 5 4 1 2 *
COMPUTER SCIENCE
0478/11
October/November 2021
Paper 1 Theory
1 hour 45 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
Calculators must not be used in this paper.
INFORMATION
●
The total mark for this paper is 75.
●
The number of marks for each question or part question is shown in brackets [ ].
●
No marks will be awarded for using brand names of software packages or hardware.
This document has 12 pages. Any blank pages are indicated.
DC (LEG/AR) 202712/4
© UCLES 2021
[Turn over
2
1
Binary is a number system that is used by computers.
(a) Tick (3) one box to show whether binary is a base-2, base-10 or base-16 number system.
Tick (3)
Base-2
Base-10
Base-16
[1]
(b) Hexadecimal and denary are number systems that can be used by programmers.
Convert these four hexadecimal values into denary values.
09 ...........................................
10 ...........................................
28 ...........................................
A1 ...........................................
[4]
Working space
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
© UCLES 2021
0478/11/O/N/21
3
2
Magda has a mobile telephone.
She uses the touch screen on her telephone to send emails to her customers. The touch screen
breaks, stopping Magda from using it to type her emails.
(a) Identify one other input device that would be built into the mobile telephone that Magda could
use to send an email to her customers.
............................................................................................................................................. [1]
(b) The touch screen operates by using the conductive properties of the object that is used to
touch the screen.
State whether the touch screen is a resistive, capacitive or infra-red touch screen.
............................................................................................................................................. [1]
(c) Magda is listening to music on her mobile telephone when she receives a telephone call. A
signal is sent within the telephone to stop the music and output that a call has been received.
Give the name of this type of signal.
............................................................................................................................................. [1]
© UCLES 2021
0478/11/O/N/21
[Tu