COMPUTING | GCSE | OCR | J275
OCR GCSE Computing
Learning Grids – H/W
Unit A451: Computer Systems and Programming
This learning grid H/W belongs to:
Name: ______________________________
Form: _______________________________
Mr. Ahmed
A451 - ATTENTION! Please read!
1. These learning grids cover the key theory content of the
OCR GCSE Computing specification. Learn them and you
will pass the exam!
2. The grids closely follow the content and order of unit A451:
Computer Systems and Programming.
• Complete each section for homework once they are
covered in your lessons!
• All sections must be fully completed!
• Once you have completed a section hand it in to your
teacher.
To help you find the information you need, the grids contain
page references to the corresponding sections of GCSE
computing book:
HODDER
OCR Computing for GCSE published by Hodder Education
(ISBN: 978-14441-7779-4).
Contents
Blank Grids ............................................................................................. Error! Bookmark not defined.
2.1.1 Fundamentals of Computer Systems ............................................................... 2
2.1.2 Computing Hardware ................................................................................. 4
2.1.3 Software ................................................................................................ 9
2.1.4 Representation of Data in Computer Systems ................................................... 11
2.1.5 Databases ............................................................................................ 17
2.1.6 Computer Communications and Networking .................................................... 20
2.1.7 Programming ........................................................................................ 26
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OCR GCSE Computing Learning Grids
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2.1. 1 Fund ament als of Comput er Syst em s
2.1.1 FUNDAMENTALS OF COMPUTER SYSTEMS
COMPUTER
SYSTEMS
HODDER: 7-16
What is a computer system?
What is the name for the
interconnections between systems?
What are the three main stages in any
system?
1.
2.
What is a system boundary? Why can
they be difficult to define?
What is the difference between generalpurpose and dedicated systems?
Difference:
Give an example of each.
Examples:
What is an embedded system?
Explain what is meant by the kernel in
operating systems.
Why is reliability important in computer
systems? Give an example of a situation
in which reliability is essential.
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3.
2.1.1 Fundamentals of Computer Systems
COMPUTER
SYSTEMS
(CONTINUED)
How can the reliability of a system be
assessed?
Why is it useful to develop systems to
standards?
Explain the difference between
proprietary and open standards.
What name is given to a standard which
develops simply through common usage?
Give an example of a computing industry
standard.
What is meant by ethics in regard to
computer use?
How has the Internet affected people's
right to privacy?
Describe two ways in which the use and 1.
disposal of computer systems can have a
negative effect on the environment.
2.
State two UK legal acts relating to
computer use, and explain the purpose
of each.
1.
2.
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2.1. 2 Co mputing H ardwar e
2.1.2 COMPUTING HARDWARE
CENTRAL
PROCESSING
UNIT (CPU)
HODDER: 19-23
HODDER: 18-45
What is the purpose of the CPU?
What are the two main components of
the CPU?
1.
2.
What cycle does the CPU carry out
continuously to process instructions?
What is meant by clock speed?
What component controls the clock
speed?
Who is credited with the idea of storing
data and programs in the same place in
the computer architecture?
What is a dual-core CPU?
In computing, what is a bus?
MEMORY
What does the ROM usually store?
HODDER: 25-30
What is virtual memory, and why is it
used?
What is a disadvantage of having to use
virtual memory?
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2.1.2 Computing Hardware
MEMORY
(CONTINUED)
What is flash memory?
Using an example for each, explain the
difference between primary and
secondary storage.
What is the purpose of cache memory?
What it the purpose of RAM?
How could the addition of extra RAM
speed up a computer? Why might this
not always be effective?
BINARY LOGIC
Why do computers operate in binary?
HODDER: 31-35
ZIGZAG: 13-15
What is a logic gate?
Name three types of logic gate.
What are truth tables used for?
What logic gate does this symbol
represent?
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2.1.2 Computing Hardware
BINARY LOGIC
(CONTINUED)
What logic gate does this symbol
represent?
What logic gate does this symbol
represent?
Draw a truth table for the following
circuit.
A
B
R=A OR B
P
What name is given to the branch of
algebra used in logic circuits?
INPUT AND
OUTPUT
DEVICES
Name three input devices.
1.
2.
3.
Name three output devices.
1.
2.
3.
HODDER: 36-41
Give an example of a device which has
both input and output functionality.
State a common application of the
device given in the previous question.
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2.1.2 Computing Hardware
INPUT AND
OUTPUT
DEVICES
(CONTINUED)
State and describe a suitable input device Device:
for a user with a visual impairment.
Description:
State and describe a suitable input device Device:
for a user with severely limited physical
Description:
mobility.
What is a sensor?
What is an actuator?
Name two input devices typically found
on a smartphone.
1.
2.
Name two output devices typically found
1.
on a smartphone.
2.
State and describe a suitable output
device for a user with a visual
impairment.
Device:
State and describe a suitable output
device for a user who is unable to
communicate verbally.
Device:
State three applications of RFID tags.
1.
Description:
Description:
2.
3.
Describe two types of printer and
suggest what applications they might
have.
OCR GCSE Computing Learning Grids
1.
2.
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2.1.2 Computing Hardware
SECONDARY
STORAGE
HODDER: 42-45
Why is secondary storage necessary?
Name the three main categories of
secondary storage device.
1.
State three common secondary storage
devices and describe a purpose for
which each might be used.
1.
2.
3.
2.
3.
Briefly describe how data is physically
written to a hard-disk.
Briefly describe how data is physically
written to a CD or DVD.
Name the five factors that are necessary
to consider when choosing an
appropriate secondary storage device.
1.
2.
What is the most common secondary
storage device used as the main storage
for desktops and laptops?
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3.
4.
5.
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2.1. 3 Softwar e
2.1.3 SOFTWARE
SOFTWARE
HODDER: 47-67
Define the term ‘software’.
HODDER: 47-67
What is a user interface?
Describe two different types of user
interface that could be used to operate
a computer.
1.
2.
Explain the difference between system
software and application software.
How can an operating system
multitask?
What is meant by memory and
peripheral management?
Give three examples of common
security features in operating systems.
1.
2.
What is meant by utility software?
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
3.
2.1.3 Software
SOFTWARE
(CONTINUED)
Name and describe two types of disk
organisation utility.
1.
2.
Name and describe two types of
system maintenance utility.
1.
2.
Name and describe two types of
security utility.
1.
2.
Explain the difference between customwritten and off-the-shelf software.
Describe one advantage to a business of
using custom-written software.
Describe one disadvantage to a
business of using custom-written
software.
Explain the difference between
proprietary and open-source software.
Describe one advantage of using
open-source software.
Describe one disadvantage of using
open-source software.
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2.1.4 REPRESENTATION OF DATA IN COMPUTER SYSTEMS
HODDER: 69-88
2.1. 4 R epresent ation of Dat a in Computer Syst em s
UNITS
HODDER: 70
What name is given for the number
system in base 10 that humans use?
What name is given to the number
system in base 2 that computers must
use to store and process data?
Why must all data be converted into
this form before it can be processed by
the computer?
Fill in the gaps in the sequence to
order the binary units from smallest
(top) to largest (bottom).
bit
byte
kilobyte
gigabyte
How many bits are there in a byte?
How many bytes are there in a kilobyte?
How many bits are there in a kilobyte?
What name is given to the unit made
up of approximately a billion bytes?
What name is given to the unit made
up of 1,024 gigabytes?
Consider a five-digit binary number.
What is the highest number that can
be stored?
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2.1.4 Representation of Data in Computer Systems
NUMBERS
HODDER: 70-76
Convert these binary numbers into
denary.
010 10101
1110 0011
Convert these denary numbers into
binary.
34
53
Convert these hexadecimal numbers
into denary.
37
C4
Convert these hexadecimal numbers
into binary.
Hint: convert each hex digit into four
binary digits and concatenate.
41
5D
Why is hexadecimal number
representation often used in
computing?
Add these two binary numbers
together.
101 1101 + 001 1010
Explain a problem that can arise when
adding two 8-bit binary integers to get
an 8-bit answer.
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2.1.4 Representation of Data in Computer Systems
CHARACTERS
HODDER: 78-79
How are individual characters
represented by a computer?
What is meant by the term ‘character
set’?
What does ASCII stand for?
How many different characters can the
ASCII set represent?
How many bits does this use per
character?
Explain the limitations of using ASCII
for global communication.
Suggest a different character set that
would be more useful for global
communication.
How many bits does this character set
use per character?
Explain one possible disadvantage to
using this character set instead of
ASCII.
Do you think that this is a significant
problem or not?
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2.1.4 Representation of Data in Computer Systems
IMAGES
What is a pixel?
HODDER: 80-83
Describe how a simple black and white
bitmap image can be stored by the
computer.
The binary numbers below represent a
simple black and white bitmap image.
On the 8 × 8 grid, fill in the
appropriate spaces to create the image.
A 1 represents black and a 0
represents white. Fill in each 8-bit
string of digits in regular reading order.
1111 1111
1000 0001
1000 0001
1000 0001
1000 0001
1111 1111
0001 1000
0111 1110
How is the storage of a colour images
different from that of black and white
images?
What is colour depth?
What is metadata?
What information might typically be
stored in image metadata?
OCR GCSE Computing Learning Grids
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2.1.4 Representation of Data in Computer Systems
IMAGES
(CONTINUED)
What is resolution?
What are the effects of colour depth
and resolution on the file size of the
image?
How do vector graphics differ from
bitmap images?
What is a possible advantage of using
vector graphics instead of bitmaps?
SOUND
HODDER: 84-86
Explain the difference between
analogue and digital signals.
Describe the process of converting an
analogue sound signal to digital.
What is meant by the ‘sample rate’ of
an audio recording?
What effect does the bit rate have on
the audio quality?
What effect do the bit rate and sample
rate have on the file size of the
recording?
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2.1.4 Representation of Data in Computer Systems
INSTRUCTIONS
HODDER: 87-88
Explain how the CPU distinguishes
between instructions and data.
What are the two parts of each
program instruction called?
1.
2.
What are registers?
What is the name of the register which
keeps the address of the next
instruction to be processed?
What is the name of the register that
stores data currently in use?
What is an address?
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2.1. 5 D ataba ses
2.1.5 DATABASES
THE DATABASE
CONCEPT
HODDER: 90-96
HODDER: 90-110
Define ‘database’.
Explain the difference between a serial
file and a sequential file.
What is an indexed sequential file?
What is a flat file database made up of?
How many tables does a flat file
database have?
What is meant by data redundancy?
Why is this undesirable?
Explain the difference between data
validation and data verification.
State three types of data validation
check.
DATA MODELS
1.
2.
3.
What is a relational database?
HODDER: 96-98
State two other database models.
1.
2.
What name is given to a subject about
which data is stored?
What is a meant by a ‘one-to-many’
relationship?
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2.1.5 Databases
DATA MODELS
(CONTINUED)
Draw a diagram which represents a
one-to-many relationship, using an
example of your choice.
What are attributes?
How are attributes stored in a data
table?
What are records?
How are records stored in a data
table?
DATABASE
DESIGN
HODDER: 98-100
What a schema?
What data structure stores schemata?
What are primary keys used for?
What quality must primary keys have
to make them useful?
What is meant by ‘mission critical’
databases?
State four decisions which must be
made about each field in the database.
1.
2.
What is a foreign key?
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3.
4.
2.1.5 Databases
What is a DBMS?
DATABASE
MANAGEMENT
SYSTEMS (DBMS) What is the purpose of using a DBMS?
HODDER: 100-109
Give three examples of ways in which
the DBMS enables protection and
security.
1.
Name and describe three different ways
in which a database can be viewed.
1.
2.
3.
2.
3.
How does the DBMS deal with
concurrency problems?
What does the acronym ACID stand for?
A:
C:
What is the purpose of ACID?
What is a query and what are they used
for?
What does SQL stand for?
Explain what is meant by the term ‘data
mining’.
Suggest one reason why many highstreet chains of shops issue electronic
loyalty/reward cards to customers.
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I:
D:
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2.1. 6 Co mputer Communic ations and N etwor king
2.1.6 COMPUTER COMMUNICATIONS AND NETWORKING
NETWORKS
HODDER: 112-136
HODDER: 112-147
What is a network?
Describe three ways in which
computer networks have improved
productivity in the workplace.
1.
2.
3.
Describe two potential issues that can
arise from the use of networks.
1.
2.
What is the function of the network
interface card?
Where can network interface cards
usually be found in the computer?
What device can be used to prevent
signal bouncing in bus networks?
What name is given to the process of
signals losing integrity as they travel
through a network medium?
What device can be used to counter
the above issue? How does it work?
Explain the purpose of a hub.
Why may using several hubs potentially
slow down a network?
What device can be used to connect
different network media and segments?
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2.1.6 Computer Communications and Networking
NETWORKS
(CONTINUED)
What is a switch?
Why are switches able to operate at
such high speeds?
Explain the difference between a level
2 and a level 3 switch?
What is the purpose of a router?
Describe the features of a peer-topeer network.
Explain the workings of the client–
server network model.
Give two advantages of using client–
server networks over peer-to-peer.
1.
2.
Give two disadvantages of using client– 1.
server networks over peer-to-peer.
2.
Outline the main features of the bus,
ring and star network topologies.
Bus:
Ring:
Star:
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2.1.6 Computer Communications and Networking
NETWORKS
(CONTINUED)
Draw a simple diagram to represent
each network topology.
Bus:
What do the acronyms LAN and
WAN stand for?
LAN:
Ring:
WAN:
Explain the primary difference between
a LAN and a WAN.
What is the function of a metropolitan
area network (MAN)?
What is a VPN?
Describe one reason why an
organisation might use a VPN.
State three mediums for transmitting
data over a network.
For each medium above, state one
potential advantage and disadvantage of
using that medium.
Medium
Advantage
Disadvantage
OCR GCSE Computing Learning Grids
Star:
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2.1.6 Computer Communications and Networking
NETWORKS
(CONTINUED)
What is a protocol?
Name and describe three common
network protocols.
1.
2.
3.
What is a MAC address?
What is an IP address?
Explain how IP addresses can be static
or dynamic.
Describe how the process of packet
switching is used to carry data across a
network.
What is meant by bandwidth?
There are likely to be several network
policies in place on your school
network. Can you identify three of
these?
1.
2.
3.
What is meant by acceptable use?
Explain the difference between back-up
and archiving.
Explain what is meant by a network
disaster recovery policy.
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2.1.6 Computer Communications and Networking
THE INTERNET
Fundamentally, what is the Internet?
HODDER: 138-146
State two of items of hardware that
are required to connect to the
Internet.
1.
2.
Describe, in simple terms, the function
of each of these hardware items.
What is the difference between the
World Wide Web and the Internet?
What is a hyperlink?
Explain the role of DNS servers and
how this relates to IP addresses.
What standard language is used to
write web pages?
Describe two other standards which
can be applied to web pages.
1.
2.
State a common Internet file standard
for images.
State a common Internet file standard
for sound files.
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2.1.6 Computer Communications and Networking
THE INTERNET
(CONTINUED)
State a common Internet file standard
for storing documents.
What is compression?
Why is it important when sending files
over the Internet?
Explain the difference between lossy
and lossless compression.
Surely lossless compression always a
better choice than lossy compression?
Justify your answer.
Give an example of a type of file for
which lossy compression should not be
used.
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2.1. 7 Progr amm ing
2.1.7 PROGRAMMING
ALGORITHMS
HODDER: 150-156
HODDER: 149-183
What is an algorithm?
Who is regarded as the first ever
computer programmer?
What was the name of the first ever
general-purpose, high-level
programming language?
State and describe two different ways
in which an algorithm can be
represented.
1.
2.
What shape on a flow chart is used to
represent a selection (decision or
choice)?
What shape on a flow chart is used to
represent an input or output?
What does this flow chart symbol
represent?
What is meant by ‘tracing’ an
algorithm?
OCR GCSE Computing Learning Grids
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© ZigZag Education, 2014
2.1.7 Programming
ALGORITHMS
(CONTINUED)
Draw a flow chart for an algorithm to
represent the following situation:
A boy leaves his house in the morning
to travel to school.
He checks the time on his watch
when he sets off. If the time is before
8am, he decides to walk to school.
However, if the time is 8am or later
he decides to take the bus.
He always follows this rule, and either
way he will reach school on time.
Ensure that you use the correct
symbols for each stage of the
algorithm.
Write an equivalent algorithm in
pseudocode for the same process.
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2.1.7 Programming
PROGRAMMING
LANGUAGES
HODDER: 156-162
What is machine code?
What is assembly language? How did it
evolve from machine code?
What defines high-level languages?
Describe the function of translator
software.
Describe each of the following
translators:
Assembler:
Interpreter:
Compiler:
What is an IDE?
Describe each of the following tools
that might be provided by an IDE.
Code editor:
Error diagnostics:
Run-time environment:
Auto-documentation:
OCR GCSE Computing Learning Grids
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2.1.7 Programming
CONTROL FLOW What is meant by ‘sequence’ in
programming?
IN IMPERATIVE
LANGUAGES
HODDER: 163-167
What is meant by ‘selection’?
Give two examples of programming
constructs which use selection.
1.
2.
1.
2.
What is meant by ‘iteration’?
Give two examples of programming
constructs which use iteration.
Read the following pseudocode
example.
Identify an instance of sequence,
selection and iteration.
1
2
3
4
5
6
7
8
9
10
11
12
HANDLING
DATA IN
ALGORITHMS
Explain what is stored by each of the
following data types:
HODDER: 168-175
START program
INPUT A
INPUT B
FOR j = 1 to 10
C = (A +B)/2
IF A=B-4
A = 6
B = 13
END IF
NEXT j
OUTPUT C
END program
Integer:
Real/float:
Boolean:
Character:
String:
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Sequence:
Selection:
Iteration:
2.1.7 Programming
HANDLING
DATA IN
ALGORITHMS
(CONTINUED)
Suggest an appropriate data type to
store each of the following data items.
The quick brown fox jumps
over the lazy dog
A
872.15
54
TRUE
Explain the difference between
variables and constants.
Explain the difference between
declaration and assignment.
What is an array used for?
What is meant by the dimension of an
array?
TESTING
HODDER: 176-183
Why is it important that programs are
tested?
What is a syntax error?
Give an example of a common cause of
syntax error.
What is a logic error?
Give an example of a common logic
error.
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2.1.7 Programming
TESTING
(CONTINUED)
Explain the difference between valid
extreme and invalid extreme test data.
If working correctly, how should a
program deal with erroneous test
data?
What name is given to test data which
is out of range and should be rejected
by the program, but is the correct type
of input?
What name is given to acceptable test
data which is in the correct range?
Consider a very simple program which
outputs whether an inputted integer
between -100 and 100 is positive,
negative or zero.
Type
For each of the different types of test
data, name the type and give two
appropriate examples of data to test
this program with.
Fundament als of Comput er Sy stem
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Example Test Data