MATRICULATION AND SECONDARY EDUCATION CERTIFICATE EXAMINATIONS BOARD
UNIVERSITY OF MALTA, MSIDA
SECONDARY EDUCATION CERTIFICATE LEVEL
MAY 2010 SESSION
SUBJECT:
PAPER NUMBER:
DATE:
TIME:
Computer Studies
IIB
4th May 2010
9.00 a.m. to 11.00 a.m.
MARKING SCHEME
Directions to Candidates
Write your index number where indicated at the top of the page.
Answer ALL questions in the spaces provided. You are not allowed to use extra sheets other than
those provided in this booklet.
Good English and orderly presentation are important.
The use of flowchart templates is permitted. The use of calculators is NOT permitted.
Question
Number
For Markers’
use only
MARKS
1
2
3
4
5
FOR MARKERS’
USE
Total number of Marks or
Grade obtained by
candidate
1. (a) Application software is used for doing particular, productive tasks.
(i)
Name the application software that is typically associated with each of the following
three terms:
Key field – DBMS – 1 mark (do not accept database or brand names)
_______________________________________________________________________
Home page – web browser – 1 mark (do not accept brand names)
_______________________________________________________________________
Cell reference – spreadsheet – 1 mark (do not accept brand names)
_______________________________________________________________________
(ii) Some application software is said to be customisable. What does this mean?
May be adapted for one’s use – 1 mark
_______________________________________________________________________
(iii) Besides application software, a computer system requires another category of software.
• What is this other category of software called?
System software – 1 mark
____________________________________________________________________
• What is the name of the most important software in this category?
Operating system
____________________________________________________________________
• This software is said to have a graphical user interface (GUI). What does this mean?
The user communicates with the computer through the use of graphical representations
____________________________________________________________________
of actions and programs - 1 mark
_____________________________________________________________________
(b) A computer system requires both input and output devices.
(i) Name the input device that is generally used for the following three tasks:
Correction of multiple-choice questions; identifying the film code in a computerised
DVD lending library; controlling an object in a fast-action computer game.
Correction of multiple choice questions – OMR reader – 1 mark
_______________________________________________________________________
Identifying the film code – bar code reader – 1 mark
_______________________________________________________________________
Controlling an object – joystick – 1 mark
_______________________________________________________________________
(ii) Use three of the following words to complete the paragraph below on output devices.
softcopy vector raster resolution hardcopy
Monitors and printers form their output as an array of dots and therefore are called raster
– 1 mark devices. The quality of the image/print depends on the resolution – 1 mark of
the device. A monitor produces a softcopy – 1 mark of the output unlike that produced
by a printer.
(c) The hard disk is the principal secondary storage device of a computer system.
(i) Provide two reasons why it is an essential component of a computer system.
Reason 1 : Stores large amounts of data
Reason 2 : non-volatile medium – 1 mark each
___________________________________________________________________________
(ii) The hard disk is an example of a magnetic storage medium. Give one example of an
optical storage medium and one of an electronic medium.
Optical storage medium : – CD OR DVD – 1 mark
Page 2 of 9
___________________________________________________________________________
Electronic storage medium : – ROM or RAM or Pen-drive – 1 mark
___________________________________________________________________________
2. (a) ROM and RAM make up the main memory of a computer system.
(i)
What unit of measurement is used nowadays to measure the size of RAM?
GB – 1 mark
___________________________________________________________________________
(ii)
Mention TWO differences between ROM and RAM.
ROM read only while RAM read and write – 1 mark
ROM permanent while RAM volatile – 1 mark
___________________________________________________________________________
(iii) What is each type of memory used for?
ROM – stores the booting up program – 1 mark
___________________________________________________________________________
RAM – stores users program and data during execution – 1 mark
___________________________________________________________________________
(b) The arrows labelled A and B below represent two buses that connect the memory unit to
the CPU.
B
A
(i)
What is the name of the bus that each arrow is representing?
A – address bus – 1 mark
___________________________________________________________________________
B – data bus – 1 mark
___________________________________________________________________________
(ii) In ONE of the circles attached to arrow A, write down the letter ‘M’ to show where
the memory unit is located.
‘M’ written in circle at front of arrow – 1 mark
(iii) The width of one of these buses is related to the word size (or word length) of the
computer system.
• What is meant by the word size?
The number of bits that can be handled in one operation – 1 mark
____________________________________________________________________
• Which of the two buses is related to the word size?
Bus B – 1 mark
____________________________________________________________________
• What effect does the word-size have on the performance of a computer system?
The wider the bus means a larger word size and thus the better the performance of
____________________________________________________________________
the system – 1 mark
____________________________________________________________________
(c) The task of the CPU is that of repeatedly fetching, decoding and executing instructions.
(i) State whether each of the following statements is True or False:
Page 3 of 9
•
A register is made up of a number of bits and is a fast, temporary storage area.
True – 1 mark
____________________________________________________________________
• The program counter keeps a copy of the instruction that is being executed.
False – 1 mark
____________________________________________________________________
• The accumulator holds the result of an arithmetic operation.
True - 1 mark
____________________________________________________________________
• The instruction register holds the data to be operated upon.
False – 1 mark
____________________________________________________________________
(ii) What unit of measurement is used for measuring the operating speed of the CPU?
GHz – 1 mark Hz & MHz should be acceptable too.
___________________________________________________________________________
(iii) What is the data on which an instruction operates called?
Operand – 1 mark
___________________________________________________________________________
3. (a) The binary number system is generally used to represent digital data.
(i) A BIT can have TWO states. What are these states called?
0 or 1, On off or True False - 1 mark
___________________________________________________________________________
(ii) What other number system is used as a shorthand notation for binary numbers?
Hexadecimal number system – 1 mark
___________________________________________________________________________
(iii) An 8-bit binary pattern in a computer system (for example 0101 1011) may be
representing a number. Mention two other different items that this pattern may be
representing.
A character (ASCII code), a pixel, an audio note, a memory address, an instruction,
___________________________________________________________________________
accept other possible answers - 1 mark each for any two valid answers
__________________________________________________________________________
(b)
Logic gates and circuits are used to manipulate the bits.
(i)
A two-input logic gate is required to output a 1 only if all inputs are 1s. Draw
the symbol of this logic gate and its truth table.
A
C
B
1 mark
(ii)
A
B
C
0
0
0
0
1
0
1
0
0
1
1
1
1 mark for correct input combinations
The following is an incomplete truth table of a logic circuit where A and B are
the inputs and Z is the output.
D
Z
A
B
C
D
Z
A
C
0
1
0
0
0
1
1
1
0
1
B
1
0
0
1
0
1
0
0
1
1
Page 4 of 9
•
•
Complete the following statement to express the function of the logic circuit in terms
of its inputs A and B.
Output Z is 1 only if A is 0 and B is 1 - 1mark
Mention one use of logic gates/circuits in a computer system.
Storage elements, registers, doing arithmetic operations, comparison, accept
____________________________________________________________________
any other valid use – 1 mark
(c) One concern of software publishers is software piracy.
(i) What is software piracy?
The illegal copying/use/installation of software – 1 mark
_______________________________________________________________________
(ii) Mention two techniques used by publishers to minimize the risk of piracy..
Any 2 from the following - entry of serial numbers, activation keys, dongles – 1 mark
______________________________________________________________________
(iii) Despite the fact that people are aware that piracy is illegal, some still tend to copy/use
pirated software. Give two reasons why they do so.
Have a larger variety of software, getting software for free – 1 mark each
_______________________________________________________________________
Page 5 of 9
4. (a) Flowcharts are used to describe algorithms.
The incomplete flowchart below generates a random number (RN) and the user is given three
chances to guess the number. Use the text in the following five boxes to complete the
flowchart.
read user’s
increment
chances =
number
chances by
get RN
RN = UN?
3?
(UN)
1
start
generate RN
set number of
chances to 0
read user’s
number (UN)
no
no
RN = UN?
increment chances
by 1
yes
chances = 3?
yes
stop
1 mark for each correct symbol
(b)
Write one or more statements in Pascal to code each of the following tasks:
For the following assign the mark/s if the delimiter (;) is left out.
(i)
Increment the value in variable count by 4.
count := count + 4; - 1 mark
_______________________________________________________________________
(ii) Display the word POSITIVE if the value in variable number is a 0 or greater. Otherwise
display the word NEGATIVE.
if number >= 0 then write (‘positive’) else write (‘negative’);
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________________________________________________________________________
1 mark for correct condition, 1 mark for correct printing.
(iii)
Use a FOR ..DO loop to display all the integer numbers from 20 to 40.
For i := 20 to 40 do
______________________________________________________________________
Writeln (i);
______________________________________________________________________
1 mark for overall loop syntax, 1 mark for correct start/end values, 1 mark for
printing output
(c) The following are sections of the same program that have some errors. The program is
supposed to process some students’ marks.
………
Write (‘Enter the number of students’);
Readln (Students);
Sum := 60;
……….
Repeat
Write (‘Enter an examination mark’);
Readln (Mark);
Until (Mark >= 0) and (Mark <= 100);
Sum := Sum + Mark;
………
Sum/Students := Average;
Writeln (‘The class average mark is ‘, Average);
………
Study the sections of the program above and then answer the following questions.
(i) Write the statement that has a syntax error.
Sum/Students := average; - 1 mark
___________________________________________________________________________
(ii) Which statement will cause a logical error?
Sum := 60; - 1 mark
__________________________________________________________________________
(iii) Which statement will generate a run-time error if a zero (0) is input by the user?
Sum/students - 1 mark
___________________________________________________________________________
(iv) What type of validation check is being performed by the Repeat ~ Until loop?
Range check – 1 mark
___________________________________________________________________________
(d) A program written in a high-level language needs to be translated into machine code.
(i)
Why is this translation required?
Computer hardware only understands machine code OR to convert the source code into
_______________________________________________________________________
executable code – 1 mark
_______________________________________________________________________
(ii)
Mention one type of software which translates a program written in a high-level
language into machine code.
Compiler or interpreter – 1 mark
_______________________________________________________________________
Page 7 of 9
5. (a) A network system is an interconnection of computers and other devices.
(i) One drawback of networking is the spread of computer viruses.
• Give one example of what a virus might do to the computer system.
Format hard disk, does not boot up, corrupts data, annoying objects across screen
____________________________________________________________________
, accept other possibilities – 1 mark
• How can a virus be removed from a computer system?
Scanning the system with an anti-virus software – 1 mark
____________________________________________________________________
(ii) What may be done to preserve the confidentiality of information before transferring it
over a network?
Encrypting the data – 1 mark
_______________________________________________________________________
(iii) Name and briefly describe two services that are available over the Internet.
E mail – sending and receiving electronic messages. Research – searching for
information. E commerce – buying, selling, marketing. IRC – chatting in real time
_______________________________________________________________________
through textual messages. Videoconferencing – communication through audio and
visual in real time. E government – online government services. 1 mark each for any
two.
_______________________________________________________________________
(b) The owner of a small stationery shop has computerised her manual operations.
The following table shows part of the Stock table of the database system:
Item code
Description
Supplier code
Quantity
5046552178
6199066322
3445654444
Felt pen green
Ruler 30cm
Copybook 24pgs
S123
S54
S123
14
5
45
(i)
Which of the four fields is the key field?
Item code – 1 mark
___________________________________________________________________________
(ii) What special characteristic must the data in the key field have?
Unique data – 1 mark
___________________________________________________________________________
(iii) Name one other field in the Stock file that must be available for producing a receipt.
Price – 1 mark
___________________________________________________________________________
(iv) The database requires another table that must have a relationship with the Stock table.
• What is this table called?
Supplier file – 1 mark
__________________________________________________________________________
•
Mention two important fields that you expect to find in the table you mentioned in
the previous question.
Company name, address, telephone, any other relevant field – ½ mark each for any
two.
__________________________________________________________________________
• Which field, common in both tables, forms the relationship?
Supplier code – 1 mark
__________________________________________________________________________
Page 8 of 9
(c) A large trading company has set up its IT department.
(i) Mention one duty of each of the following IT department personnel:
IT trainer – organisation/delivery/designing of IT related courses to the staff –1 mark
__________________________________________________________________________
Web master – designs/uploads/maintains company’s website – 1 mark
__________________________________________________________________________
Computer technician – repairs hardware faults – 1 mark
__________________________________________________________________________
(ii) The following six tasks are performed by the systems analyst. Write them down in the
correct order.
Testing, Changeover, Maintenance, Design, Analysis, Feasibility study.
1. Feasibility study
2. Analysis
3. Design
4. Testing
5. Changeover
6. Maintenance.
½ mark each
Page 9 of 9