KCSE Past Papers 2017 Computer Studies Paper 1 (451/2)

Questions and Answers

2017 Computer Studies – Paper1

1. State the meaning of the term computer software. (2 marks)


  • It is a set of programs written in a computer language to direct a computer on how to perform a particular task or behave in a certain way.2. State three features of fifth generation computers. (3 marks)


  • Use of expert system
  • Support the use of natural language
  • Support distributed computing
  • Support artificial intelligence and voice recognition.
  • Support parallel processing
  • Small in size/ portable
  • Superior hardware and software
  • consume less power3. Differentiate between home page and web page as used in the lnternet. (2 marks)

    – It’s the first page that opens when a site is opened using the When the domain name.

    – It is web document in a website/ Any page on a web.

    4. State three characteristics of mainframe computers. (3 marks)


  • They have bigger memory capacity.
  • Have high processing power.
  • It supports multiprocessing.
  • Supports large number of users at the same time/ Supports several peripheral devices.
  • Runs so many applications at the same time.5. The management of an organisation intends to purchase a printer. State three factors that they should consider during the purchase (3 marks)


  • Volume of work to be printed.
  • Maintenance cost below e.g. consumables like toners should be affordable.
  • Speed of printing.
  • Type of work to be printed; type of paper, paper size/user needs /range of capability.
  • Type of printout whether colour is required or not.
  • Compatibility with the existing hardware
  • Initial cost
  • availability of in the market
  • Portability / physical size6. Describe each of the following computer cables:

    (a) Parallel cable; (2 marks)

    – It is a communication cable which has high speed of transmission and transmits several bits at the same time.

    (b) Serial cable; (2 marks)

    – It is a communication cable which has low speed of transmission and bits follow one another in sequence or are transmitted one at a time.

    7. A computer technician has observed a lot of dust on computers in the computer laboratory.

    State three precautions that need to be put in place to avoid this. (3 marks)


  • Fit ventilating / air conditioning system to allow free circulation of air.
  • Fit curtains on the windows / add a curtain net to reduce dust entry into the laboratory.
  • Regularly use of a blower or vacuum cleaner/mob to blow dust from the computer parts.
  • Avoid entering the laboratory with materials that may have dust such as shoes8. Explain the term proofreading as used in word processing. (2 marks)

    – It is the process of using appropriate proofing reading like spelling and grammar checkers and autocorrect features to check whether the document has typographical or grammatical errors.

    9. State the function of each of the following computer keyboard keys when using a word processor:

    (a) End (1 mark)

    – Used for moving the cursor to the end of the line been typed or already typed.

    (b) Insert (1 mark)

    – Used for changing typing mode from insert mode to type over and vice versa (Accept the description of type over and insertion).

    (c) Backspace. (1 mark)

    – Used to delete a character to left of the cursor position.

    10. Explain two problems associated with the computer hard disk. (4 marks)


  • Excessive shock like dropping it on the hard surface may cause the platters to dislocate hence reading may be a problem
  • Contact with strong magnetic fields or static electricity may affect the device since data is saved magnetically.
  • If the case containing the platters is opened, dust may get into it causing disk crash,
  • Some viruses may create virtual tasks which will eventual cause the disk to be overwork hence causing it to crash
  • Sporadic power failure may cause the disk to crash.11. State the spreadsheet function that can be used to obtain each of the following values in a worksheet:

    (a) Number of cells with values in a column. (1 mark)

    =Count ()

    (b) Mean of values in a range of cells. (1 mark) =Average ( )

    12. A school intends to install wireless media in their communication system. State three advantages of this mode of communication media. (3 marks)


  • The school will find it easy to add or remove modes on the system.
  • Incase of new building is put up, there will be no need of interfering with the communication media.
  • Users will find it safer to move around as there are no wires around the rooms.
  • Students will be able to roam as they access the network.13. State two ways in which one can create a password which cannot be easily accessed by hackers.(2 marks)


  • By including many characters in a password
  • By combining different characters in a password
  • Use password generator manager.14. State two ways through which a computer user can minimise Repetitive Strain Injuries (RSI)associated with the use of a computer. (2 marks)


  • Taking regular break intervals when using a computer.
  • Use an ergonomic keyboard to avoid stress.
  • Support wrist with wrist rest pad when using a mouse.
  • Use of standard furniture/proper sitting posture.15. Identify four tasks that can be achieved using a Desktop Publishing programme from the following list of tasks. (2 marks)

    I. Managing students records in a school

    II. Creating a calendar

    III. Designing a building structure

    IV. Creating a banner

    V. Creating a book cover

    VI. Processing of examination results

    VII. Creating business cards


  • Creating a calendar.
  • Creating a banner.
  • Creating a book cover.
  • Creating business cardsSection B Answer question 16 and any other three questions from this section.

    16. (a) State two qualities of a good pseudocode. (2 marks)


  • should be short and clear/ precise
  • should have start and end clearly shown.
  • Statements should be clearly defined.
  • should depict the logical flow of solving the problem.
  • should not be ambiguous.
  • it should be indented /neat / legibility(b) With the aid of flowchart diagrams, describe each of the following programme control structures:

    (i) sequence (3 marks)

    a) Program statements are executed one after the other in the order in 2 which they appear.

(ii) selection (3 marks)

Flow of a program is determined by a choice of one of two or more 2 options based on a condition given

(c) Draw a programme flowchart that would accept three ntunbers and find their sum. If the sum is greater than 200. It adds 30 to the sum, otherwise subtracts 20 from the sum. The programme should then display the results. (7 marks)

  • 17. (a) Describe three arithmetic errors that may occur during computerised data processing. (6 marks)

    Arithmetic errors

  • Truncation error Results due to shortening or leaving out part of a number or a word.
  • Rounding off error , F Arising by approximating a number by replacing it with a number that has fewer significant digits or one with zeros for its ending digits.
  • Overflow error Occurs when the results of a computation is larger than the allocated memory space.
  • Underflow error 1 Type of error occurs when the output is low small to be represented in the chosen format
  • (b) Arnold a programmer intends to create a user input interface screen for a system. State three factors that he should consider. (3 marks) 
  • User interface design considerations
  • Should be user friendly.
  • Colour, fonts and layout should be appealing to the user.
  • Consider a consistent layout in the entire system.
  • Should prompt user clearly.
  • Should capture the same number of items of date as indicated in the manual data capture form.(c) With the aid of an example in each case describe the following types of maintenance. (i) adaptive; (2 marks)

    – Type of maintenance that is done to make the system to adopt the changing technology e.g. changing the system because to new o/s

    (ii) perfective; (2 marks)

    – Type of maintenance done to make the system better in its operation e.g. adding a module in a system.

    (ii) corrective. (2 marks)

    – Type of maintenance done to correct an error in the system e.g. wrong results during addition.

    18. (a) Distinguish between a microwave transmission and a radio transmission. (4 marks)


(b) Figure 1 shows a computer, network topology Use it to answer the questions that follow.

  • (i) Identify the type of topolgy

    – Bus topology

    (ii) State the function of each of the parts labelled A and B. (4 marks)

    A – The Bus cable It is a core section of the bus topology network which has all the nodes connected to it and data pass through it.

    B – Tenninator It destroys data that does not reach its destination so that it doesn’t cause echo back.

    (c) A computer laboratory experiences power supply problems. Describe three power related problems that should be addressed. (6 marks)


  • Blackout: This is unexpected discontinuation of power supply in the laboratory.
  • Power sage: Sudden drop of voltage levels that lasts less than a second.
  • Transients/ surge: High voltage flowing.
  • Brownout: Partial blackout where there’s low voltage flow.
  • Short circuit: live wires touching each other’s
  • Loose connection, which may cause tripping or total power failure.19. (a) A school has been advised to employ a database administrator. State three responsibilities of this personnel in the school. (3 marks)


  • Carrying out school database backups. El Recovering of lost school data incase of system failure.
  • Ensuring the security and integrity of the school system.
  • Adding new users to the school system and managing the user’s accounts.
  • Designing and developing database application for the school.
  • Updating or maintaining database for the school.(b) Explain two ways in which computers can be used in the transport industry. (4 marks)


  • Use of GPS to track vehicles, flights etc.
  • Bookings to different destinations can be done through the use of computers ( online booking).
  • The computers can also be used to reduce the speed of vehicles and bring sanity in the industry.
  • Managing human resource involved in the industry.(c) Mary was advised to partition a hard disk for her computer. Explain two reasons that may have necessitated this. (4 marks)


  • For security purposes, incase one partition fails the second partition remains functional.
  • If she requires backup copies to be stored in the same hard disk.
  • If she intends to install more than one operating system.(d) Explain a reason for conducting each of the following studies in systems development: (i) Schedule feasibility; (2 marks)

    – To determine if the proposed solution can be developed within the required time.

    (ii) Technical feasibility. (2 marks)

    – To determine if the system can be supported by the available technology.

    20. (a) Explain three functions of an information system in an organisation. (6 marks)


  • Process data in an organization according to the policies and objectives.
  • Decision making by providing information that helps with strategic planning within the organization.
  • Means of communication and flow of information to various sections of an organization / enable sharing of information.
  • Improving quality of production, through the use of feedback mechanisms for counter checking the production with expected results.(b) Explain two benefits that a company would gain from using batch processing method for data processing (4 marks)

    Benefits of using batch processing.

  • Output is increased because the processor work is uninterrupted.
  • Low cost of operation since the tasks are processed as a group.
  • Requires little supervision since the processing runs automatically as long as the instructions are given.
  • Less labour required since the process is automatic.
  • Efficient use of computer resources due to no idle time.
  • Gives company opportunity to check any error before processing begins.(c) (i) Convert the number l 1101.112 to its decimal equivalent. (3 marks)


(ii) Perform the following binary operation 110112 + 1012 (2 marks)


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