KCSE Past Papers 2018 Computer Studies Paper 1 (451/1)

2018 Computer Studies – Paper1

1. Reasons for the preference for laptops.


  • They are small and fit in a small storage space.
  • They are light weight hence can be carried to areas where their services are required.
  • The monitor, system unit, keyboard units are attached together hence making its use to be convenient.
  • Rechargeable / backup battery. Any 2 x 12. Reasons for the use of command — line interface OS


  • They do not take up a lot of memory hence boot faster than the GUI OS.
  • They have direct access or most hardware devices.
  • They are cheaper to acquire as some can be downloaded free of charge. They can run on lower —bit hardware systems such as 32-bit computers. Any 3 x 13. Measures to be put in place in the laboratory to safeguard user health.


  • All power cables must be insulated and hidden from users.
  • The furniture used must be of standard computer furniture.
  • The room should be lit with adequate lighting.
  • The room must be ventilated.
  • Computer monitor should be fitted with antiglare to filter excess light rays emanating from the monitor.
  • Avoid slippery floors/cemented floors.
  • Controlling dust.4. Ways in which barcode readers can be used in a school.


  • To take inventory of items in the school.
  • To keep track of employee login log out.
  • Used to transact business in the library.
  • Used to keep track of movement of goods.5. Advantages of flat panel monitors.


  • They are compact and light weight;
  • They consume less power;
  • They do not suffer from geometrical distortions;
  • They do not cause eye fatigue.
  • They support many advanced technologies;
  • They can be made in almost any size and shape; They support higher resolution.
  • Low heat radiation.6. Reasons why daisy wheel printer are in extinct.


  • They supported one font size and font face;
  • They were monochrome printers;
  • They produced noise while printing;
  • They were very slow;
  • Did not print graphics.
  • Had poor print quality.7. Ways in which an OS secures computer system:


  • Access controls: Authentication of users in order to access files;
  • Performing regular patches of updates;
  • Creating secure accounts with required privileges;
  • Scrutinizing all incoming and outgoing packets of data through a firewall;
  • Encryption of data, during the transmission stage; Password / biometric analysis;
  • Log files to detect any breach. Any 3 x 18. Advantages of hardcopy output.


  • – They are acceptable as exhibit in cases of litigation.
  • Can be used without a computer.
  • They are difficult to change without leaving any trace.
  • They can be used without power.
  • They can be used without the experience of computer usage. Any 2 x 19. (i) Thesaurus:

    It is a feature in a word processor that suggest words with similar or opposite meaning to the selected word @l.

    (ii) Comments:

    It is a feature in WP that allows a user to attach a remark about the selection @l.

    10. Multilevel list:

    It is a format style that shows the listed items of different levels rather than one at one level.

    Each level has different indentation and numbering style @2.

    Example (Accept any)

    1. Chapter One


    Definition of terms @l.

    11. Distinction between real-time and distributed OS.


  • Real-time OS reads information from input devices and must respond within a short duration of time to ensure correct performance.
  • Distributed OS distributes computation among several physical processors which do not share memory or clock.12. Function of protect sheet:


  • It is a feature used to prevent unwanted changes to be made on the data contained in a sheet by limit the ability to make changes.13. Computer based careers created by introducing computerized data processing.


  • System analysts Hardware technicians
  • Data entry clerks
  • Programmers Networks techniciansDatabase administrators


  • Web designers
  • Network administrator14. = If (A1 > 10, Al * 77, Al * 50)

    Compares the value in cell Al If it is greater than 10, if comparison is True, the results of operations Al * 77 is displayed, if it is False the results of the operations Al * 50 is displayed.

    15. (a) Identifying technologies that could be used in the system.

    — System ana1ysis/ information gathering/problem recognition (@ 1)

    (b) Identifying the shortcoming of the old system

    — Problem definition

    (@ 1)

    (c) Prepares the software migration plan

    — Implementation stage (@ 1) 3

    Section B (60 Marks) Marking Scheme

    16. (a) Looping is the control structure that allows a block of code/statements to be repeated until a certain condition is fulfilled. @ 2 marks

  • Accept any type of looping control structure
  • (c) Distinction between a source program and compiler 
  • Source program is the original computer based instructions written by a programmer in a programming language whileA compiler is a program that processes statements/instructions and translates them into machine language.

    17. (a) (i) Search-engine

    It is a web-based application used to locate for an item or information from world wide web.

    (ii) Factors that affects duration of download


  • The size of the video
  • The band width of the media used
  • Availability of network
  • Other activities that may be running in the computer.
  • Other restrictions enforced in the computer
  • The restrictions by the ISP
  • Speed of computer (Any 3 @ l)(b) Causes of Wakulima system’s failure


  • Lack of power supply to the system servers.
  • Network infrastructure breakdown/poor network coverage/lack of connection.
  • Program failure in the system/malware (virus).
  • Hardware failure in the system.
  • Human action which could be accidental or intentional.
  • Lack of access rights.
  • System overload (Any 4 @ 1 mark)(c) (i) Cropping

    Used when handling a graphic and there is a need to remove some of the portions in the graphic.

    (ii) Transparency

    Used when there is a need to make the background of a graphic to be visible.

    (d) Areas where infra-red radio waves are used.


  • TV remote control communication; DVD remote control communication
  • Communication between peripheral devices and the computer
  • Data link over short distance using mobile phones Radio remote control
  • Remote locking / opening doors/devices18. (a) Activities at the planning stages


  • Identify opportunity for the new project.
  • Analyse feasibility to establish the viability of the project.
  • Develop a work plan.
  • Identify appropriate staff to work in the project.
  • Control and direct the project.(b) (i) Technical Feasibility

    Meant to determine whether the proposed solution is technically practical/establish whether the technology is available /expertise is available. (@ 2)

    (ii) Economic Feasibility

    Meant to establish whether the proposed system will be cost effective. (@ 2)

    (iii) Schedule Feasibility

    Meant to establish whether the system can be implemented within an acceptable time kame. (@ 2)

    (c) (i) Primary keys in the table Table 1 : Dept code @

    Table 2 : Student’s Registration No. @

    (ii) Benefits of referential integrity in the table


  • No record can be added to the table 2 if its corresponding record in Table 1 does not exist.
  • No record in Table 1 can be deleted without first deleting associated records in Table 2.
  • Reduces data redundancies.
  • Prevent deletion of related tables. (Any 2 x 2)19. (a) (i) Preserve check

    It is a measure placed used to ensure that data item is in its original status. (@ 2 marks)

    (ii) Data type check

    It is a measure that ensures that correct data type is entered for each field. (@ 2 marks)

    (iii) Check digit

    This is a number calculated by the computer to make sure that the other numbers in a sequence have been entered properly. (@ 2 marks)

    (b) (i) BCD

    Binary Coded Decimal

    (o i)

    (ii) EBCDIC

    Extended Binary Coded Decimal Interchange Code.

    (iii) ASCII

    American Standard Code for Information Interchange

  • 20. (a) (i) I. Router It is the device meant to forward data packets between computer network in the school and the internet. (@ 2 marks)

    H. Firewall

    It is a device that prevents unauthorized access to or from a private network (school’s LAN) (@ 2 marks)

    III. File server

    It is a computer attached to a network whose purpose is to provide location for shared disk access (shared storage of computer files). (@ 2 marks)

    (ii) Software to be installed in a computer


  • Network operating system
  • Browser/Mozi11a,firefox Necessary system drivers to supports installed hardware 
  • Protocols(SMTP,HTTP) (Any 2 @ 1 mark)(b) Use of computers in research for data management
  • Used for data manipulation;
  • Computers aid in data capturing;
  • Computers can be used to store researched and analysed data;
  • Information in computers can be a secondary source of data;
  • Computers can be used to generate reports;
  • Computers can be used to communicate researched work. (Any 4 x 1)(c) Advantages of online application services and shared processing resources.

    Users will not be required to have powerful processing devices;

  • Users can access the services from anywhere in the world;
  • Users can access services at any time (24/7);
  • Users can offload their data to the cloud infrastructure;
  • Users can collaborate with remote users to process the data;
  • The approach will cut out high cost of hardware;
  • Sharing of resources;
  • Faster access to service;
  • Cost effective;
  • Orders are made without going to the shop. (Any 3 x 1)
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