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Q&A-KCSE Computer Studies Paper 1

Explain how the techniques of

(i) verification,
(ii) validation
are used to ensure that the stored data is as accurate as possible.

Dual input of data

  • Two inputs are compared by the system and any discrepancies are reported (and not stored.)
  • Data input once, either printed out or checked on the screen and  errors corrected

 Rules are given to the processor

  • Only accept A, B, C, D, E, F, G i.e Any other input rejected.

Drop-down list/radio buttons

  • Provides only valid inputs, so no other validation is required

Give one advantage using a star network rather than a ring network.

  • star - if one computer goes down the others can still be used
  • ring - if one computer goes down the others can not be used

802.3 is the standard for ethernet wired networks and 802.11x is the standard for ethernet
wireless networks.
Outline why standards such as these are important in the development of network devices and
software.

  • Standards specify a set of rules for hardware and/or software used in network communications. Because all manufacturers must adhere to the standards when manufacturing network hardware or software, it means that all devices should be able to communicate, regardless of manufacturer.

KCSE Computer Studies Paper 1, 2001

SECTION A (40 MARKS)

ANSWER ALL THE QUESTIONS IN THIS SECTION

1.Compare the two types of diskettes used in microcomputers in terms of physical size and densities.    (2mks)

2.Why is it necessary to have a UPS in a computer laboratory?  (2mks)

3 a) Explain what is meant by batch processing   (1mk)

   b) Give one advantage and one disadvantage of batch processing ( 2mks)

4. List any four high level programming languages  (2mks)

5.A 3 by 4 matrix M is to be added to another 3 by 4 matrix array N so as to give a third 3 by 4 matrix array P.  Using a high level programming language, write a program segment that assigns the sum of M and N to P.(4mks)

6. The first column in the table below contains the formulae as stored into the cell F10 of a spreadsheet.  Enter the formulae, as they would appear when copied to the cell M20 of the same spreadsheet.  (3mks)

           

Formula in F10

Formula in m20

=D10* E10

 

=A$ 25

 

=$ D$13

 

                                                                                                                                                                 

7.  Give three advantages of separating data from the applications that use the data in database design. (3mks)

8.  Explain the impact of information on organizations in each of the following areas:  (2mks)

   a) Competition

   b) Pace of growth

9. a) List any four tasks that an electronic spreadsheet should be able to perform other than calculations  (2mks)

    b) Explain what is meant by automatic recalculation as used in a spreadsheet.(1 mk)

10. Describe the functions of the following computer hardware components:

   a)Mouse                     (2 ½  mks)

   b)Scanner.                   (1 ½ mks)

11. a)State two differences between Disk Operating System (DOS) and WINDOWS operating system.

 b. i) Define the term application software  (1mk)

     ii) Give one example of application software (1mk)

12. a)  Give one difference between internal and external commands in Disk Operating System.   (2mks)

      b)  Name two DOS commands that may be used for checking disk errors.  (2mks)

13. Explain how a paragraph can be moved from one place to another in word-processing. 2mks)

14.  Define the term structured programming. (2mks)

SECTION B (60MKS)

Answer question 15 and any other three questions from this section.

15.a)  What is meant by each of the following terms:

 i)   pseudocode        (1 ½ mks)

  ii)  Flowchart           (1 ½ mks)

b) a program is required to list the first 1000 numbers in the series:  2, 4, 6, 8,

10. Draw a flowchart and write a program that can be carried out this task.   (12 mks)

16. The following car details are to be entered in a database; make, date-of-manufacture, colour and cost.

 a) Prepare a suitable database structure showing field names and their field types   (5mks)

 b) Explain how you index the data such that cars of the same make and colours are together   (2mks)

 c)  Write a statement that can be used to select cars of the colour green        (2 mks)

 d) Give an instruction that would;

  i)select cars whose cost lie between 500,000/= and 1,000,000/=  (3 mks)

 ii)Determine the average cost of all cars         (3mks)

17.  a)The diagram below represents the essential features o a computer system. Study the diagram and answer the questions that follow:

 

i)Name the components (4mks)

            A

            B

            C

            D

ii) On the diagram above, indicate the direction of data flow using arrows.  (3mks)

b) Name the three types of buses in a computer system (3mks)

c) Explain how CPU registers may be used to carry out a basic calculation such as:2 + 7 = 9

d) Name two computers output devices. (1 Mark)

18. a)State three ways in which computer technology may affect employment patterns in organizations   (3mks)

b) State three ways in which computer technology may affect employment patterns in organizations (3mks)

c)Suggest three strategies that can be employed to manage resistance to change  (3mks)

d) Give three advantages of computerization in an organization.  (3mks)

19. a)In a computer based information system, state the purpose of the following files and give one example where such a file may be required in a school.                (8mks)

i) report file

ii)Back-up file

iii)Reference file

iv) Sort file

b) State three precautions that should be taken to ensure that diskettes are well stored.  (3 mks)

c)  Distinguish between “serial” and Indexed sequential” file organization methods.  (2mks)

d)  Distinguish between binary and octal number systems and give an example of each  (2mks)

 

There are four change-over methods used in the implementation stage of the system development life cycle (SDLC): direct change-over, phased, parallel and pilot.

Direct Change-Over

  • A date is chosen for the shutdown of the old system, then at that time, the old system
    is turned off and the new system is implemented

Phased

  • Parts of the new system are implemented in stages or for a period of time, both the old and the new system are running together until all parts of the system are implemented.

Describe one way developers ensure that their software addresses inclusivity issues.

Incorporate language support features in their software, which allows users to select their preferred language. This can be achieved through multi-language user interfaces and providing translation capabilities. By doing so, developers address language barriers and make the software accessible to a broader audience, demonstrating a commitment to cultural inclusivity.

Gender inclusivity – use gender-neutral language in examples

Cultural/Racial inclusivity – use a variety of ethnicities in photos

Ability inclusivity – represent awareness of disability in some examples

Sexual preference inclusivity – use language that is supportive of LGBTQI+ people

Suggest two advantages of using robots, instead of humans, to build cars in the factory.

  • more efficient than a human
  • more accurate than a human
  • can lift larger and heavier equipment than a human
  • can replace humans working in a dangerous environment
  • reduces running costs, such as wages and overheads
  • can produce consistent results/output
  • can work 24 hours a day // do not need to take breaks.

 

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.

  • a computer that responds to requests to provide information and services over the Internet - an Internet server
  • defines how messages are transmitted and formatted over the Internet-HTTP
  • software that enables users to access/view documents and other resources on the Internet - Browser     
  • numerical ID for each device on the Internet-IP address
  • unique ID for a network interface card  -MAC address

A computer operates as a binary digital device. Explain why binary is used to represent computer data.

  • Binary can represent two states because computer circuits use transistors, which can either be on or off

Name three types of cables used in data communication

Twisted pair cables

Coaxial cables

Fibre optic cables

Website data is broken down into packets to be transmitted to a user. Describe the structure of a data packet.

It has a header

  • that contains the destination address
  • that contains the packet number
  • that contains the originator’s address

It has a payload

It has a trailer.

 

Your friend wishes to install a wireless network in his office. Explain to him the difference between guided and unguided media

  • Guided media uses cables to connect to computers whereas unguided media uses waves.

Utility software are operating system programs designed to maintain the functionality of a computer system.

Describe three types of utility software that are provided to help maintain the security and integrity of computer data.

  1. Virus scanning / Anti-virus. Used to locate and delete viruses / scans and compares files with databases of known viruses.
  2. Firewall: checks data packets / examines source address / filters out unexpected packets.
  3. Back up. Copies data onto a separate storage device for use if the original data is lost or corrupted.

What characterises a phased implementation approach?

  • Phased means that only one part of the system is implemented at a time

A web server has an internet protocol (IP) address. Give three characteristics of an IP address.

  • consists of values between 0–255 / 0–FFF
  • values are separated by full stops/colons
  • it is a unique address
  • can be static or dynamic
  • can be public or private
  • can be IPv4 / have four groups of digits
  • can be IPv6 / have eight groups of digits
  • in IPv6 :: can replace groups of zeros.

Differentiate between active matrix and passive matrix LCDs

 

  • Passive matrix create images by scanning the entire screen whereas active matrix displays are made using thin-film transistors technology(TFT)
  • active matrix  display has a higher resolution compared to passive matrix
  • Active matrix consume more energy than passive matrix

Which files are backed up in an incremental backup scheme?

  • Any new or changed files since the last backup

State the reasons for system review and maintenance

  • user changes his mind
  • new government legalisation/company policy company changes
  • changes in hardware
  • changes in software/upgrades/new versions
  • improved operating efficiency/ease of use

A family has purchased a computer system with the following specification:

Processor speed 2200 MHz
RAM 512 Megabyte
Hard disk drive 120 Gigabytes
CD ROM
DVD writer
Modem 56k
Monitor 17"

(a) The computer has been purchased for buying goods and services over the Internet. Explain how each of these items of hardware would be used for this purpose.

Hard disk drive

RAM

DVD writer
Modem

Hard disk drive

  • to hold the operating system/communication and applications software/ISP software
  • for storing files/information/cookies on backing store

RAM

  • for data, computer programs and operating instructions which are moved into it/downloaded for data currently in use

DVD writer

  • Films/videos/pictures/music/multimedia data downloaded/purchased

Modem

  • link/dial up/establish communication with the Internet
  • Convert digital signals to analogue/audio tones (and vice versa) Which can travel across the telephone system

Fibre optic cable is available in either single-mode or multi-mode. Outline the characteristics of each mode.

  • Single-mode fibre consists of a narrow core in which all light pulses travel at the same speed and arrive roughly at the same time at the destination.
  • Supports higher bandwidth with less signal loss over a greater distance
  • Multi-mode Multi-mode fibre consists of a larger core in which multiple light pulses can travel down the core.
  • Supports a smaller bandwidth and signals attenuate at a shorter distance than single mode fibre.