KCSE 2019 Computer Studies Paper 1 Questions With Marking Scheme

SECTION A

Answer all the questions in this section

1. State the hardware technological differences hardware technological differences between the second generation and the third generation computers. (2 marks)
2. State two ways of ensuring proper ventilation in a computer room. (2 marks)
3. Convert the decimal number 20.373 to its binary number system equivalent. (3 marks)
4. Peter has installed internet in his home computer in order to use it for browsing. State three ways in which he would prevent viruses from infecting the computer. (3 marks)
5. State three ways of transforming a picture embedded in a Desktop Publishing programme in order to fit in a designated space on a document. (3 marks)
6. Differentiate between a line printer and a page printer as used in computers. (2 marks)
7. Describe virtual reality as used in computers. (2 marks)
8. State the function of each of the following features of an email software:
   1. Inbox (1 mark)
   2. Draft (1 mark)
9.  
   1. Explain the term toggle key as used in computer keyboard. (2 marks)
   2. List examples of toggle keys on a computer keyboard. (2 marks)
10. State the type of error that would occur in data processing for each of the following cases:
    1. Entering the number 315 instead of 351.(1 mark)
    2. Entering the text "Kwys" instead of "Keys". (1 mark)
11. State four factors to consider when selecting an input device for use in a computer room. (4 marks)
12. State three functions of Un-interruptible Power Supply (UPS). (3 marks)
13. Distinguish between a page break and a column break as used in a word processor. (3 marks)
14. State three factors to consider when selecting an operating system to instal in a computer. (3 marks)
15. Differentiate between analogue data and digital data as used in computers. (2 marks)

SECTION B

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

16.  
    1. Explain the term dry running as used in program development. (2 marks)
    2. Explain three properties of an algorithm. (6 marks)
    3. To quality to get a driving license, an applicant must be 18 years or over. Ten candidates applied for the driving license test. Draw a flow chart that would read the name and age of an applicant and display the names of those who qualify. (7 marks)
17.  
    1. State four outcomes that may result from using incorrect requirement specifications during systems development. (4 marks)
    2. A school opted to use direct change over approach when installing a new system. Explain three challenges that the school may face as a result of this approach. (6 marks)
    3. State three reasons that may lead an organisation to instal an intranet (3 marks)
    4. The figure below shows a coaxial cable. State the function of the part labelled A. (2 marks)
       
18.  
    1. State three hardware devices that may be required to connect a computer to an existing local area network. (3 marks)
    2. A publisher intends to use a desktop publishing programme to create a publication which is to have many graphics. State three ways in which the graphics may be acquired for this purpose. (3 marks)
    3. Interpret each of the following spreadsheet formula:
       1. = countif(D2:09,">"&B4) (2 marks)
       2. =sumif(B3:B11, "4M", D3:011) (2 marks)
    4.  
       1. The following are the fields of products table in a database created to store records of products manufactured in a factory:
          • product number
          • product name
          • price
          • product description
            1. State the appropriate data type for each field. (2 marks)
            2. State three properties to be put in place during table design to ensure integrity of the data entered. (3 marks)
19.  
    1. Explain three features of a graphical user interface as used in computers.(6 marks)
    2. State the function of each of the following computer keyboard keys:
       1. Caps Lock (1 mark)
       2. Shift (1 mark)
       3. Home (1 mark)
    3. Using twos complement notation, determine the value of the operation 25₁₀ − 29₁₀(6 marks)
20.  
    1. Distinguish between Computer Aided Instruction (CAI) and Computer Aid (CAL). (4 marks)
    2.  
       1. State four activities that may be carried out when disposing off an old system in an organisation. (4 marks)
       2. State four ways of getting user specifications during systems design. (4 marks)
    3. State three benefits gained from the advancement in technology in the music industry. (3 marks)

MARKING SCHEME

1. The 2nd generation use transistor in its logic circuit while the 3rd generation used integrated circuit.
2. Ways of ensuring proper ventilation in a computer room
   • Having large windows
   • Having windows and vent area opened
   • Using air conditioning equipment
   • Providing spacious seating arrangement
     First 2 x 1
3. 20.375 to binary
   • 20= 10100,
     .375 x 2 = 0.750
     .750 x 2 = 1.500
     .500 x 2 = 1.000
     The integer digits read down=011
     20.375₁₀ = 10100.011 ~
4. Ways to prevent viruses in a home computer connected to the Internet
   • Using antivirus shielding software
   • By surfing smart, i.e. those site which are credible
   • Using a firewall to deter unwanted packets from accessing the computer from the intemet
   • Install anti-spyware to prevent real time spying of the computer
   • Not using storage media which has been used in suspicious computer
   • Using complex and secured password to restrict access
   • Enabling security settings of the bowser
     First 3x1
5. Ways of transforming a picture in a PTP
   • Rotation
   • Flipping
   • Cropping
   • Stretching
     First 3x1
6. Difference between a line printer and a page printer
   • A line printer is an impact printer that prints one entire line of text at a time while a page printer is a non impact printer that prints a whole page at a time.
7. Virtual Reality is the computer generated simulation of a three-dimensional image or environment that can be interacted with in a seemingly real or physical way by a person using a specialized electronic head gear.
8.  Function of
   1. Inbox: A storage location where new email messages are stored. @l
   2. Draft: A storage location where messages composed but not yet sent are stored. (W1
9.        
   1. Toggle keys:
      • These are keys that alternate the input mode. When pressed ON they are intended to perform a task, when OFF, they perform different task. @ 2
   2. Example of toggle keys:
      • Caps lock, Insert, Num Lock and Scroll lock.
        First 2 x ½=1
10.        
    1. Transposition error
    2. Transcription error
11. Four factors to consider when selecting input devices.
    • Compatibility with the existing system
    • Cost of the device
    • The extra features in the device
    • The purpose of the device
    • The speed in which input of data is required
    • The nature of data to be captured.
      First 4x1
12. Functions of UPS
    • Protects devices against high or too low voltage.
    • Provides temporary power supply in case of sudden power outage
    • Processing wave form distortion.
    • Stabilizing the frequency
    • Surge protection.
    • Suppress transverse mode noise.
      First 3 x 1
13. Distinction between page break and column break
    • Page break is a code inserted by a WP program that instructs the printing device where to end the current page and begin the next.
    • Column break is a feature that breaks a column and starts the next column.
14. Factors to consider when selecting an operating system. 
    • the hardware configuration of a computer
    • The type of computer in terms of size and make
    • User friendliness of the operating
    • Number of users it can support
    • Number of processors and hardware it can support
    • Reliability and security provided by the OS.
      First 3 x 1
15. Distinction between Analogue data and digital data,
    • Analogue data uses values that change continuously between to instances while
    • Digital data are values that change from one value to the next in a step by step sequence.
16.    
    1. Meaning of dry running.
       • Dry running is the process where a programmer manually works through a code to trace the values of variables and identify any error.
    2. Properties of an algorithm.
       • Finiteness: An algorithm must always terminate after a finite number of times steps.
       • Definiteness: Each step must be precisely be defines using an action to be performed at each step of the algorithm.
       • Input: Any operation performed needs beginning value associated with different activities in the operation.
       • Output: An algorithm must have a form of output/results/expected value/ qualities.
         First 3 x 1
    3.      
       
       
       Start = 1
       Stop = 1
       Initialize Counter = 1
       Input name = 1
       Input age=1
       Precise age=1
       Output name = 1
       Decision Loop=1
       Increment = 1
       Logic = 1 marks
17.          
    1. Results of incorrect requirement specifications
       • The system may be costing more than what was projected
       • The system will be delivered later than schedule
       • The system will not meet the user's expectation
       • The cost of maintaining and enhancing the system may be excessively high.
       • The system may be unreliable and prone to crrors and downtime.
       • The system will not meet legal requirements.
         First 4 x 1
    2. Challenges that the school may face as a result of using direct change over.
       • If something went wrong in the new system, there will be no fall back has the business has to stall till the problem is sorted.
       • There will be a period of time where no system is available because the old one is switched off and the new one is being switched on.
       • There will be a period of upheaval while the system is brand new and the school staff are finding their way around it.
       • There is a possibility of sabotage by staff since there is no time to monitor and manage resistance to the new system.
         (First 3 x 2 marks)
    3. Reasons for installing an intranet in an organization
       • Used to isolate the organizational resources from the internet/security.
       • Used to provide communication and collaboration among individual within the organization/remote control.
       • Used to publish and share valuable information among the users easily, inexpensively and effectively via portals and intranet website/resource sharing.
       • Used to run critical applications that support business decision making. Distributed processing facilities.
       • Cost Effectiveness.
       • Protects signal distortion.
       • Protects signal inteferance.
         (First 3 x1 =3)
    4. Function of core insulation of a coaxial cable
       • Used for blocking electromagnetic fields from entering the cable and producing noise.
       • Provides insulation.
18.         
    1. Required components to connect to a LAN
       • A network adapter/network interface card
       • Network medium/cable
       • RJ45 connectors/BNC/ST connector/SC connectors/Fibre local connector
       • Data points (sockets to plug in the cable)
       • Switch/Hub
       • Access point/TP link
         (First 3x1)
    2. Ways of acquiring the graphs to use in a DTP
       • Using digital camera
       • Scanning the graphics from other sources
       • Downloading from the internet
       • Drawing from scratch/Drawing tools
       • Clip art
       • Another file
         (First 3x1)
    3.      
       1. = Countif (D2: D9, ">" & B4)
          • Count those value in the range D2 :D9 with values greater than the value in cell B4). @ 2
       2. = Sumif (B3: B11,"4M" D3: D11)
          • Sum the values in the cell range D3: Dil for records whose corresponding values in cell range B3 : B11 equals to “4M"@2
    4.           
       1. Data types used in the table
          • Product Number - Number/Autonuinber/Text
          • Product NameText/string
          • Price - Currency/Number
          • Product Description - Memo/Text/String
       2. Properties that can be set in the table design
          • Data type
          • Validation/Validation rule
          • Input mask
          • Setting required/null value status
          • Field size
          • Caption
            First 3 x 1
19.           
    1. Features of a GUI
       • Windows-a rectangular area on the screen where the commonly use application run.
       • Icons - A picture or symbol which is used to represent a software application or hardware device.
       • Menus-a list of options from which the user can choose what that they require.
       • Pointer - a symbol such as arrow which moves around the screen as the user move the mouse.
         (3 x 2 marks)
    2.         
       1. Function of Caps lock
          • It's a toggle key when ON, the characters typed are in uppercase when OFF, the characters typed are in lower case. @1
       2. Shift key -
          • Used to enable uppercase letter to be printed when alphanumeric keys are pressed. @l
          • Used with other keys to modify behavior/function key.
       3. Home key
          • Used to take the cursor to the beginning of the line in a word processor. @ 1
          • Evidence of movement of the cursor.
    3. 25.-29.
       • 25 = 0001 1001
         29 = 0001 1101
         2's Comp(29) = 1110 0010+1 = 1110 0011
         Adding the two binary numbers
         0001 1001
         1110 0011
         1111 1100
         No carry bit hence 2's complement of the sum is obtained and the resulting is negative
         2's Comp(1111 1100) = 0000 0011 +1 = 100₂
         = -4₁₀
20.          
    1.    
       • Computer aided instruction is an interactive instructional technique/ drill and practice whereby a computer is used to present the instructional material and monitor the learning that takes place.
       • Computer aided learning is the use of computers to aid in the education or training.
    2.         
       1. Activities that may be carried out when disposing an old system.
          • Confidential information must be removed/Backup.
          • All accounts or access control facilities associated with the equipment must be destroyed.
          • Installation of the new system.
          • All potential clues such as configuration settings must be destroyed
          • Storage devices which had sensitive information should be destroyed.
          • The equipment to be disposed in proper manner.
            (First 4 x 1)
       2. Ways of getting user specifications during system's design
          • Sampling of existing documents
          • Conduct research and visits the sites
          • Observation of work environment
          • Use questionnaires
          • Conduct interviews
          • Use prototyping approach
          • Use Joint Requirement Planning (JRP)
          • Automated method
            First 4 x 1
    3. Benefits gained by music industry from advancement in technology.
       • Few raw materials are used in the production of the media
       • No more need for big warehouses to store music materials
       • Delivery companies has less volume of deliveries
       • The use of online material is environmental friendly.
         (First 3 x 1)