IB 1 Term1 Test 1, 2012
Thursday, 4th October 2012 (Lesson 3&4)
1 hour
[MARK SCHEME]
Page:1 of 6
Question 1.
An author has broken his arm and can no longer use his computer to complete an article.
The operating system of the computer provides many utilities that can make it possible
for people with a wide range of disabilities to use their computers.
(a) Define the term operating system.
[1 marks]
Answers may include:

correct reference to software

manages the hardware and software resources of the system

manages the memory – optimises use of RAM

file management – locates files and programs requested

provides the user interface

provides a (software) platform on top of which other programs (applications) can run.
(b) State two utilities provided by an operating system that would be helpful in
enabling the author to use his computer effectively despite his injury.
[4 marks]
Answers may include:

sticky keys – for accessing capital letters, control sequences etc.

voice input – alternative to typing

filter keys – to ignore accidental repetition of keystrokes

mouse keys – control mouse with keyboard

onscreen keyboard – to provide an alternative to a physical keyboard (as long as it is
clear that it is provided by the operating system).
Allow other utilities if they are reasonable and related to an arm injury and clearly provided
by the operating system.
[1 mark]: for each feature identified up to [2 marks], and an additional [1 mark] each for the
relevant description up to [2 marks].
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Question 2.
a) Distinguish between shareware and freeware.
[2 marks]
To distinguish between means to demonstrate a clear understanding of similar terms
Shareware is software distributed freely, but with certain conditions applying to it.
Either the software is released on a trial basis only, and must be registered after a
certain period of time, or in other cases no technical support can be offered with the
software without registering it. In some cases direct payment to the author is
required.
Freeware on the other hand is a software program that’s available for use without
any charge attached to it. This doesn’t mean the program isn’t copyrighted. Usually,
the originator retains the copyright. Anyone can use it, but the program can’t be
legally sold or distributed without permission.
b) State four tasks performed by an operating system
Answers may incude:
-Loading programs and subroutines.
The programs and data are to be loaded from the storage system before they can be
processed. The loading of other system programs or software into the main storage i.e. a
compiler is handled. The duty also includes the swapping of application programs between direct
main storage and direct access storage, and the calling into main storage and linking together the
applications or systems subroutines to be used together with particular jobs.
-File security and management.
Ensures that unauthorized users do not gain access to the computer files i.e.
i). Use of pass word to prevent illegal access or amendments to user of systems files
ii). Copying file contents for use incase of losses.
iii). Maintaining all the file descriptions and their locations.
-Input and output control.
It is composed of a set of routines to manage or control the input from and output to the
peripherals. These routines are part of the executive. Control over hardware resources e.g.
control over the selection and operation of devices used for input/output or devices for Storage
(control over selection of input/output devices).
-Provision of error correction routines
The programming errors can be channeled to the user incase an interrupt is not attended to
promptly then data may be lost during the transfer and such may be recovered by setting up the
read process again.
-Communication with the operator
Normally through the keyboard the operator has to deal with errors missed by the operating
system and re-establishing the systems failure. The communication routines include:
i). Operators to computer
- Command language to load jobs or other software.
Command language to call routines for faults.
Command language to terminate the job.
ii). Computer to the operator
Report end of jobs.
-Report job usage i.e. lapse time and CPU time used.
-Error message.
-Ask for commands.
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-Interrupt handling
Entails different users connected to the CPU via keyboard terminals and all running different
programs on the computer at the same time. Done by the executive, which determines the cause
of the interrupt. The causes of the interrupt may include or be caused by: -Power failure
-Arithmetic or logical error
-Clock
-Input/output interrupts.
-Protecting hardware, software and data from improper user.
-Memory management.
Memory Management i.e. calls into Main Storage of programs and sub-routines as and when
required. Storing, retrieving, erasing and copying data files or programs on magnetic storage.
Supports various file organization methods.
-Job sequencing
Passing of control from one job (job sequencing) to another under a system of priority when more
than one applications program occupies Main Storage (i.e. provision for multi-programming
operations).
-Furnishing a log of events
Provision of the events or jobs and keeping track of their execution and hardware use. Furnishing
a complete recording of all that happens during processing. Usually in the form of a printed log.
(Logging the system). Operating Systems can keep record of what the human operator is doing.
[4 M]
Question 3.
Answer the following questions:
a) Define Application software.
[2 marks]
To define means to give a clear and precise account
Application software is any computer program or software designed for a
particular purpose, such as home finance, education, graphic design,
telecommunication, database management, or word-processing.
d) Define Bespoke software
[2 marks]
Software which has been developed in-house for use within the same institution,
organization or firm.
e) Explain what a public domain software is:
[2 marks]
Programs that are NOT copyrighted because their authors intended to share them
with everyone else are in the public domain. The UNIX community has developed a
number of such programs over the years. Programs in the public domain can be used
without restriction as components of other programs. When reusing such code, it is
good to understand its history so that you can be sure it really is in the public
domain.
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Question 4.
Define the following computer terms:
[10 Marks]
a) Clock speed
The rate at which a CPU executes instructions OR the measure of the number of
instructions processed by the computer CPU per time.
b) Hertz
The number of cycles / oscillations per second
c) Motherboard
Also called system board; It is a printed circuit board that contains the main
electronic circuits in a computer system.
d) Radio tag
It is an electronic device that uses RFID (Radio frequency Identification)
technology to transmit radio waves to another compatible device, usually for
identification and/or verification purposes.
e) Computer probe
It is a software or hardware sensor that takes in data input (usually automatically
and continuously) for further processing.
Question 5.
For each of the following situations, state the best suited application
software needed (Brand / market names are not acceptable).
a) Developing a school magazine with lots of pictures, nice page design layouts, and
varied columns.
[1 M]
Desk top publisher
b) Keeping records of high school students in a school.
Data base
[1 M]
c) Keeping marks of students in a clear analyzed and summarized why in terms of
mean scores, high scores and percentage conversions.
[1 M]
Spreadsheet
d) Making presentation in an end year speech & prize giving day for the IB students.
[1 M]
Presentation software
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Question 6.
a) State two reasons why it is better to use a smart card as opposed to magnetic stripe
card
[2 marks]
The magnetic stripe in magnetic stripe card can easily be erased or scratched making
the card useless; comparatively, the electronic chip in a smart card cannot be easily
scratched or erased
The magnetic stripe card when exposed to a strong magnetic field / equipment can lose
the stored data ,making the card useless while smart card does not suffer from magnetic
/electromagnetic interference.
Question 7.
a) What is formatting a disk?
[2 marks]
It is the process of dividing a disk into tracks and sectors for the purpose of
storing data in it.
b) What is the capacity of the 8GB flash disk in Bytes (B)? – You do not need a calculated
for this task and also exact answer is not needed (round off your numbers) but you
need to show how you arrived at your answer.
[4 marks]
1GB = 1024MB
1MB = 1024 KB
1KB = 1024B
Therefore 1GB = 10243 B
8GB = (8 X 10243) B = 8,589,934,592
(This long – exact – number is not necessary, 8 X 10243 B is enough )
[TOTAL MARKS 40]
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