Computer Studies Paper 1 Questions and Answers - KCSE 2021 Past Papers

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SECTION A (40 marks)

Answer all the questions in this section in the spaces provided

  1. State two ways in which a computer could be used in the health care sector other than record keeping. (2 marks)
  2. State four operations that may be performed on a file by an operating system. (2 marks)
  3. Explain the term website as used in the Internet. (2 marks)
  4. Explain a reason necessitating governments to enact data protection laws. (2 marks)
  5. The following data is to be entered in spreadsheet cells:
    1. 0922 111 000
    2. 31/01/2022
      State the cell format, other than the text format, that can be applied to the respective data cells in  order to appear as it is. (2 marks)
  6. When an image inserted in a desktop publishing document is selected, handles on its place holder appears. State three uses of these handles.  (3 marks)
  7. State a circumstance under which dry-run testing is performed when developing a program. (2 marks)
  8. State two ways in which data validation is implemented on an input form of a database application. (2 marks)
  9. Mikal has been employed as a computer trainer in an organisation. State three roles that she is likely to play in the organisation. (3 marks)
  10. List three electronic data processing modes used in computers. (3 marks)
  11. Distinguish between data collection and data capture as used in data processing. (4 marks)
  12. Describe each of the following features of a graphical user interface operating system:  
    1. Pointer (2 marks)
    2. Desktop  (2 marks)
  13. State a circumstance under which each of the following input devices may be used:
    1. Optical character reader (1 mark)
    2. Optical mark reader (1 mark)
  14. State the characteristics of an impact printer. (3 marks)
  15. Describe each of the following features of a word processor:
    1. Hyphenation (2 marks)
    2. Status bar (2 marks)

SECTION B (60 marks)

Answer question 16 and any other three questions in this section.

    1. The following are segments of programming languages A and B respectively:
      A 00100                      B SELECT name, class
         00111                           FROM studentsDetails
                                             WHERE House "Athi Boys"
      1. Identify the generation of programming language used in each respective segment.  (2 marks)
      2. State two advantages of each of the generation of programming language labelled A and B. (4 marks)
    2. An organisation intends to increase salaries of employees using the following rates:
       Current Salary  Percentage Increment
       Greater than or equal to 70000  5%
       Greater than 50000 and less than 70000  8%
       Less than or equal to 50000  10%
      Write a pseudocode that reads the total population of employees in the organisation and then performs the following for each employee:
      • Reads the current salary
      • Compute the increment
      • Display current salary, increment and the new salary.
        Hint: increment = current salary percentage increment rate  (9 marks)
    1. Distinguish between octal number system and binary number system. (4 marks)
    2. Subtract 1710 from 2310 using 8-bits one's complement leaving the answer in binary notation. (4 marks)
    3. State four ways in which a graphic designer would use a computer in a media company. (4 marks)
    4. State three functions of an operating system in respect to disk management. (3 marks)
    1. Explain three benefits of e-commerce to a company that deals with importation and selling of cars. (6 marks)
    2. A systems analyst intends to study an existing system. State five reasons for this study. (5 marks)
    3. Distinguish between usability testing and functional testing as used in system development. (4 marks)
    1. Explain the purpose of each of the following features of a spreadsheet chart:
      1. Legend (2 marks)
      2. Data series (2 marks)
      3. Data marker (2 marks)
    2. A school intends to install a computer network. Explain three challenges that the school may experience after the (6 marks)
    3. Xpat ICT company has been tasked to construct a network for an organisation. Explain three factors that the company should consider when selecting the media for the connectivity. (3 marks)
    1. State the functions of each of the following protocols as used in computer network:
      1. SMTP  (1 mark)
      2. FTP  (1 mark)
      3. DNS   (1 mark)
    2. State two characteristics of each of the following network topologies:
      1. Mesh topology (2 marks)
      2. Ring topology (2 marks)
    3. With the aid of a diagram, describe a centralised computing configuration. (4 marks
    4. Explain each of the following computer security threats:
      1. Social engineering (2 marks)
      2. Vulnerability. (2 marks)




 Ways in which computers are used in health care.

  • Telemedicine: A doctor can use a computer to treat a patient who is in a remote location (or the doctor could be in a remote location)
  • Data analysis: Performing laboratory analysis and to match samples Communication: Computer network media are used to facilitate communication between stake holders in the health industry.
  • Dedicated computers: Health care equipment embedded with computers used to perform special functions
  • Security: computerized devices are used to provide surveillance of a health centre
  • Computers support hospital information management system that help to make accurate decisions
  • Medical Imaging: a high resolution image generation of human body
                                                                                                          First 2x1











 2.  Operations that can performed on a file by the Operating System











  • A group of related web documents stored in a web server and linked together such that a user can jump from one section of a document to another section or to another file.
    NB: Web page/Internet page/virtual space                                         2 or 0






 Reasons for enactment data protection laws by a government

  • The government being compelled to protect individual and organizational fundamental rights to personal information.
  • To safe guard privacy





 Cell Formats

  1. 9022 111 000 - Custom format /Autonumber/Number/General  (1 mark)
  2. 31/10/2022 - Date
                          Date/Time or Value                                               (1 mark)





 Uses of image handles

  • Resizing the image
  • Increasing the image
  • Decreasing the mage
  • Rotating the image
  • Tilting the image
  • Stretching the image
  • Changing shape
  • Moving the image
  • Flipping over the image
                                                                                                         First 3 x 1










 Circumstance under which dry-run testing is performed.

  • When there is a need to identify manually the logic flaws in a program by using sample data to trace through it.
    NB: To check for error
  • To check if program is working 
  • Manual running of program                                                             2 or 0






 Ways in which data validation is implemented on an input form.

  • Using displayed comments to guide/alert a user.
  • Using controls which restrict the type of data to be entered. 
  • Using error triggers to alert a user when wrong data is entered.
  • Using appropriate data type during the design of the table.
    NB. Mark restricting points e.g. Data types, input masks, primary key, list boxes, field size, validation rules, required, lookups, format, caption, default value,                                                                                First 2 x 1








 Roles of a computer trainer in an organization.

  • Train workers to use computers hardware and software
  • Develop training materials
  • Evaluate learning outcomes
  • Establish learning needs 
  • Provide user support
    NB: Look for evidence of training                                                     First 3x1







 Electronic data processing modes

  • Real time processing
  • On-line processing
  • Time-sharing processing
  • Distributed processing
  • Batch processing/Offline
  • Multiprocessing
  • Multiprogramming
 Data collection  Data capture
 It is a process of gathering original data from the source  It is the process of obtaining data in a computer in a sensible format.

NB. Look for evidence of collecting data against evidence of entering data
                                                                                                       0,2 or 4







 Features of a GUI operating system.

  1. Pointer
    • It is a symbol that appears on the display screen which is moved using pointing devices in order to select an object or a command.
      NB. Accept device name/definition of pointing device   (2 marks)
  2. Desktop
    • It is the area on the display screen where icons representing different programs are placed.
      NB. Allow Starting point/first screen/welcome screen/homepage 
      (2 marks)









Circumstances under which the following input devices are used

  1. Optical Character Reader
    • Used when the text on a paper is to be instantly converted to machine readable formats.
      NB. Allow evidence of direct capture/scan including examples of usage e.g. stick control                                                          (1mark)
  2. Optical Mark Reader
    Used when some detailed marks on a paper are to be recognized in a computer formats.
    NB. Allow evidence of usage in Marking multiple choice questions, lottery
    tickets etc                                                                                         (1mark)










  Characteristics of an impact printer

  • Produces noise while printing
  • There is physical contact with
  • paper/striking
  • Has low consumable costs
  • Useful for bulk printing
  • Can print multipart copies
  • Has few colours
  • Low quality printouts/mono chrome
  • Is a character printer
  • Has slow printing speed
  • Has low resolution
  • Has few fonts/limited fonts
  • Has one size of font size
  • Has poor graphics 
  • Has one type of font style













 Features of a Word Processor:

  1. Hyphenation
    • It is a feature which allows a word to break lines between the syllables in order to have uniform spacing between words.
      NB. Accept illustrations                                                      (2 marks)
  2. Status bar
    • It is the area at the bottom of word processing screen that can be made to display options such as page, number, word count, permission etc.
      NB. Allow strip used for communication purposes
      Displays currently running tasks                                          (2 marks)









                                                                                                                    TOTAL  40
      1. - First Generation (1 GL)/Machine level/low level 1 mark
      2. - Fourth Generation (4 GL)/High level/SQL 1 mark
      1. - Advantages of First Generation (1 GL)
        • They are translation free
        • Can be directly executed by a computer
        • Programs written are executed very first
        • Programs written are executed efficiently by the CPU
        • The program written utilize the memory in an efficient manner because it is possible to keep track of each bit of data.
        • Stable/Hardly crashes                                                First 2 x 1
      2. - Advantages of Fourth Generation (4 GL)
        • The program are machine independent/Portable 
        • The program are easy to learn
        • Easy to understand
        • The languages provides better communication   First 2 x 1
  2. Pseudocode
    Input TotalEmployee

    While count TotalEmployee
           Input Employee salary
           If salary > 70,000then
                Increment = 5/100 x Employee salary
           Else if Employee salary> 50,000 Then
                Increment = 8/100 x Salary
                Increment = 10/100 × Salary
            End if
           New salary = Salary + Increment
           Count = Count +1
           Print Employee salary
           Print Increment
           Print New Salary
    End while
    Accept the correct use of any other loop construct

    Marks award guide
    Start/Stop 1
    Input No of Employee 1
    Decision (accept any two correct decision 2
    Computing new salary (Salary+Increment) - any one increment 1
    Looping - any evidence of looping 1
    Output 1
    Calculating New increment 1
    Logic 1

































  1. Differences between Octal and Binary number system.
    • Uses eight digits 0, 1, 2, 3, 4,5,6 and 7
    • The maximum value of a single digit is 7
    • Each position in a octal represents a specific power of 8
    • Uses less number of digits to represent a number
    • is base 8
    • A digit is represented by three bits                                           Any 2 x 1
    • Uses two digits 0 and 1
    • The maximum value of a single digit is 1
    • Each position in a binary represents a specific power of 2
    • Uses more number of digits (bits) to represent a number
    • is base 2
    • each digit is represented by 1 bit
      NB. One difference is enough for 4 marks
      Correct one sided fact award 2 marks                                     0, 2 OR 4

  2. 2310 − 1710 (Using 8-bits one's complement)
    Converting to bits
                   2310 = 000101112
                   1710 = 000100012  (1 mark)
    One's complement (17)
                                  =11101110 (1 mark)
              Adding to 23 +00010111
                                    100000101 (1 mark)
                                                 + 1
                      Answer     00000110 (1 mark)
    NB. If eight bits have not been used then award a maximum of 3 marks
  3. Ways in which a graphic designer would use a computer
    • Use the computer to take photos to be inserted in the design
    • Use a graphics program to design graphics
    • Use a computer and a scanner to directly capture images
    • Use a computer to source graphics from the internet
      NB. There should be evidence of working with graphics design
                                                                                                         First 4 x 1
  4. The Operating System could perform each of the following disk management
    • Disk formatting: preparing a disk to store data
    • Disk partitioning: Creating a logical storage block in a disk/Scan disk/Check disk
    • Defragmentation: rearranging scattered related data in order to consolidate on the used space
    • Disk diagnostics: establishing the health status of a disk
      disk compression: Compact data space so as to create extra space
    • Data backup:
    • Creating a copy of original data
    • Virus/malware scan,
    • Creating a startup disk
    • Disk cleanup    First 3 x 1































  1. Benefits a car selling company gains from e-commerce
    • Accessibility: the clients would be able to access the services from any part of the world.
    • Compliance with health requirement of social distancing hence reducing the risks of infections within the company.
    • The business would be conducted 24/7 from any parts of the world
    • Analysis of customer preference can easily made hence tailoring the
    • Analysis of customer behaviour so as to be able to easily predict the outcome of any event
    • Use the internet media to easily communicate with the customers
    • Sales campaigns can easily be run on the platform to attract more clients.
      NB. Look for enhancement to the company
      (Accuracy, Speed, Security, Ease, Accessibility, Reliability)
                                                                                                    First 3 x 2
  2. Reasons why a system analyst would consider studying an existing system
    • In order to understand the organizational structure.
    • To determine the sources of data in the organization.
    • To establish the flow of data within the organization.
    • Accuracy and timelines aspect of the data handling process.
    • To establish the data storage mechanism.
    • To identify the type of data processing used.
    • To identify the reports being generated at various stages.
    • To establish user requirements.
      NB. Check for challenges/problems and user requirements
      Also ensure the candidates answer is in respect of the current system
                                                                                            First 5 x 1
      Usability testing 
      is mainly concerned with the ease in which a user could use the application
      NB. User friendly                                                                (2 marks)

      Functional Testing - is concerned with establishing whether the system is meeting its objectives.
      Workability of the system/performace                                 (2 marks)
























  1.  Purpose of each odf the following features in a spreadsheet chart.
    1. Legend
      • It is a brief description of data in the chart alongside each data items.
        Accept the term KEY
        Accept illustrations                   (2 marks)
    2. Data series
      • It is the collection of data points which corresponds to the data within a single row.
        Look for evidence of data used to plot chart
    3. Data marker
      • It is a symbol on the chart that represents a single value in the worksheet.
        Look for evidence of value/symbol on the chart representing values
                                                                                  (2 marks)
  2. Challenges that a school may experience after installing a computer network
    • Cost of installation: the school will be reeling from the expenses asociated with the installation of the network
    • Maintenance cost:The school would ahve to incur extra expenses to ensure that the network is fucntioning as intended. Thsi includes hiring a personnel to manage it.
    • Security for personal and school data from getting into the wrong hands.
    • Malicious software would easily spread from one computer to another through the network.
    • Extra measures would be require to control access to information.
      Guiding points are 
      1. Costs
      2. Security
      3. Social ethics
      4. Skills
        NB; Accept any network related problem. e.g attenuation, server failure e.t.c                                                     First 3 x2 
  3. Factors to consider when selecting the media for connectivity.
    • Cost: the cost of acquiring, installation and maintenance of the network.
    • Transmission distance - twisted pair, infrared and radio transmit only for short distance. Fiber optics can transmit for long distance.
    • Security: how data on transit
    • Security of media.
    • Error rate: the degree of susceptibility to interference by external factors such as magnetism.
      Additional points
      NB. Accept points on authenticity, warranty, ease of handling, compatibility, system requirements, upgradability, portability, user needs, user friendliness                                       First 3 x2 




















  1. Functions of the following network protocols
    1. SMTP - Simple Mail Transfer Protocol
      • It is used to transfer email over the network or internet. (1 mark)
    2. FTP - File Transfer Protocol
      • It is used to upload and download the files over a network (1 mark)
    3. DNS
      • It is used to resolve domain name to the IP address and vice versa. (1 mark)
    1. Characteristics of mesh topology
      • Every node in the network is connected to every other nodes/Point to Point
      • It is used in Wide Area Network to interconnect Local Area Networks
      • It is reliable since there are several routes to pass data
      • Failure of a node does not affect the network
      • Failure of a media does not affect the network
      • It is reliable
      • Uses many cable connections
        NB. Accept illustration of mesh topology that is correctly labelled
                                                                                             First 2 x 1
    2. Characteristics of Ring topology
      • Devices a Pagerin 10 ed in 15 losed loop +
      • All devices have equal access to media.
      • Devices waits for its turn to transmit data.                      First 2 x 1
  3. Centralised Computing
    • It is a network design where processing is centralized and dumb terminals are used to request services from a mainframe. The mainframe is used to store all the data
                                                                                      Description @2
                                                                                      Drawing @2

  4. Security threats:
    1. Social engineering
      • It is a technique used by a hacker to steal data by using psychological manipulation combine with social scene.
      • Act of soliciting for software information from unsuspecting user
                                                                                                  (2 marks)
    2. Vulnerability
      • It is a weakness, design problem or implemenation error in a system that can lead to unexpected or undesirable event regarding security system.
      • These are weak access points                                           (2 marks)





































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