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Q&A-KCSE Computer Studies Paper 1

Distinguish between operating system software and an application software

  • OS controls operation of system/hardware
  • Applications software allows the system to do something useful
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Identify the protocol used to transfer data in networks.

  • TCP/IP
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State the difference between radio waves and microwave transmission

  • Radiowaves are omnidirectional while microwaves propagate in one direction at a time(unidirectional)
  • Radiowaves can be propagated over long distances through sky mode while microwaves require a relay satellite to amplify and retransmit the microwaves signals to the receiver earth station
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Describe the purpose of the
(i) control unit
(ii) memory unit
(iii) arithmetic logic unit

in a computer.

i) To manage the execution of instructions
By running a clock
To decode instructions
(ii) To store OS
To store those parts of applications programs currently running
To store data currently in use
(iii) Part of the processor where data is processed/manipulated
All I/O must pass through here

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Explain why a developer, who is good at both low-level and high-level programming, would normally use high-level languages when writing programs                                                                                    [4 marks]

  • High-level languages have built-in functions;
  • High-level languages have built-in libraries;
  •  High-level languages have more support/help;
  • High-level languages have structures (such as selection and iteration);
  • High-level languages can be less machine-dependent/more portable;
  • It (usually) requires fewer lines of code to be written;
  • It is (usually) quicker to develop code in high-level languages;
  • It is easier to find mistakes in code;
  • The code is easier to maintain//understand;
  • • It is easier to structure code in high-level languages;
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State ways in which an OS secures a computer system

  • Access Controls: Authentication of users in order to access files
  • Performing regular patches of updates
  • creating secure accounts with required privileges
  • scrutinizes all incoming and outgoing packets of data through a firewall
  • encryption of data, during transmission
  • Log files to detect any breach
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Explain the function of the protect sheet feature in the spreadsheet program

  • It is a feature used to prevent unwanted changes to be made on the data contained in a sheet by limiting the ability to make changes
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An organisation that supplies audiobooks over the internet is moving into a new office building.
 (a) One reason for networking devices is to provide access to the internet.
  (i) Give two other reasons for connecting devices to networks.
 

  • Share peripherals/devices (e.g. printers, scanners)
  • Communicate (e.g. email, instant messaging, play games)
  • Share data (e.g. files/music/videos/backups on servers)
  • Deploy/update applications
     
     

Describe the role of a repeater when used in a network.

a repeater will amplify a signal and resend it to overcome reduction in signal strength (attenuation) because over a distance network signals diminish in size/amplitude (are attenuated) due to characteristics of the media.

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Describe an environmental issue related to the disposal of computer components

Many components that go into computer systems are toxic and dangerous to the environment if released or disposed of inappropriately.
Heavy metals are used in batteries and circuits and these can pollute groundwater or kill animals if left exposed on landfill. Large quantities of plastics are used in systems, which take a long time to break down, some of the plastic will eventually break down into toxins as it degrades.

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Explain each of the following function of an operating system

Job scheduling/Process scheduling                                                                                              (2mks)

  • Operating systems allocate tasks/processes/jobs to the CPU using priority and FIFO principle

 Memory management                                                                                                                  (2mks)

  • OS allocates and de-allocates memory spaces to processes loaded into the RAM
  • Swaps processes between main memory and virtual memory created in the secondary storage
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State two reasons for the increased use of computers in offices                      (2 marks)

  • They are small and fit in a small storage space
  • They are portable hence can be carried when need to be used outside the office
  • Low power consumption
  • Have rechargeable batteries
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State three different methods that allow people to communicate using the Internet. In each case, give a different benefit for the stated method.

emails: fast delivery of messages (to recipient’s mail box)
able to send attachments
can store messages for later use
auto-translation no language problems
can open email at a convenient time
video conferencing/calling/chat:
removes need to travel (saves time and money)
allows face to face discussions
works in real time (only allow once)
VoIP: much cheaper than normal international calls
direct communication between people
works in real time (only allow once)
chat rooms/instant messaging:
instantaneous reply
anyone can join in
social networking:
can ensure only your “friends” are in communication
usually free to join and use
talk to (multiple) friends at the same time

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List three types of errors that are likely to exist in a program                             (3 marks)

Syntax errors-Incorrect use of programming language

Logical errors- The program do not give the expected output

Runtime errors- Premature end of a program

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Computer Studies KCSE 2006 Paper 1

SECTION A (40 MARKS)

1.What is meant by

    a)Analogue data

     b)Digital data                           (4 mks)

2. Distinguish between transcription and transposition types of errors and give an example of each  (4mks)

3. a)What are peripheral devices?  (1mk)

   b)Give two examples of peripheral devices  (1mk)

4a)What meant by the term user-friendly as used in software development? (1mk)

  b)Distinguish between the terms single-tasking and multi-user as used in operating systems  (2mks)

5.What actions should be taken in case of a fire outbreak in the computer laboratory?  (4mks)

6a) What is an Internet Service Provider?    (1mk)

  b) An employee in a business company is charged with the responsibility of putting the company advertisements on the Internet.

 i) State the professional title of the employee. (1mk)

ii) Give an example of software used by this employee to carry out the above task.    (1mk)

7.Differentiate between COM ports and LPT ports     (2mks)

8.Explain two ways in which ICT can enhance commerce.  (2mks)

9. Explain the following software terms:

    a) Portability       (1 mk)

    b) Modularity      (1 mk)

10. a) State two application areas of desktop publishing software. (2mks)

     b) Explain the following graphic terms:                                                                                     

     i) Rotate (1 mk)

    ii) Crop  (1mk)

12. a)List two arithmetic operations that can be performed on a row of numeric data in a word processing table.    (1 mk)

     b) In each case of (a) above, write the expression used.  (2mks)

13. List two methods of gathering information during the system development process   (2mks)

14.Name three types of optical disks.(3mks)

15.The diagram below shows a formatted plate surface of a storage disk.

 

 

 

            Shade and label:

            a)         one sector                                                                                ( 1mk)

            b)         One block                                                                                (1mk)

SECTION B (60 MKS)

Answer question 16 and any other three questions from this section in the  space provided

16 a) List two examples of:

       i) Third generation languages    (2mks)

       ii) Object oriented languages    (2 mks)

b) Draw a flowchart to compare three non-equal numeric values A, B, C and prints the largest of the three. (11 mks)

17 a) One of the functions of an operating system is job scheduling.  Explain what is meant by job scheduling.   (1mk)

    b)List and explain three types of user interfaces.                      (6 mks)

    c)Describe the following categories of software:

       i) Firmware                 (1mk)

       ii) Proprietary software  (1mk)

     d) a new company XYZ intends to go into the business of desktop publishing. Advise the company on three computer hardware system specification features to consider as a measure of enhancing performance. (6 mks)

18. a) distinguish between the following sets of terms as used in spreadsheets.        (2mks)

     i)Worksheet and workbook

     ii) Filtering and sorting

     b) State one way in which a user may reverse the last action taken in a spreadsheet package.        (1 mk)

     c)The following is a sample of a payroll. The worksheet row and column headings are marked  1, 2, 3, .  and A, B, C.  respectively

 

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Give one reason why use of video-conferencing has increased over the last ten years.

– faster communications now widely available
– safety reasons, e.g. increase in terrorist attacks on international flights
– reduced transportation/accommodation/hardware costs
– environmental issues, e.g. reduced carbon footprint
– increase in multinational working

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
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Distinguish between real-time and distributed operating systems (KCSE 2018)

  • 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
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State advantages and disadvantages of the following system implementation strategies

Phased:
Advantages:

  • only a small part of the operation affected if new system fails
  •  no need to pay for two sets of wages

Disadvantages:

  •  time consuming (each part needs testing fully before expanding system)

Pilot:
Advantages:

  • if new system fails, only that part will be affected
  • possible to gradually train staff on pilot before whole system changes over

Disadvantages:

  •  time consuming (waiting to see how pilot works before rolling out to rest of the organisation)

Direct:
Advantages:

  •  less likely to malfunction since fully tested
  • immediate benefits/less time wasted
  •  reduced costs (only one system so no need to duplicate staff)

Disadvantages:

  • disastrous if the new systems does fail

Parallel:
Advantages:

  •  if new system goes down, there is a backup system in place
  • possible to gradually train staff/staff have time to get used to the new system

 

 

 

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Give two reasons why hexadecimal is often used instead of binary in computer
science.

  • hexadecimal is easier (for humans) to read (than binary);
  • numbers are displayed in a more compact way (in hexadecimal than in binary);
  • it is quicker to type in (hexadecimal numbers than binary numbers);
  • it reduces the risk of typing errors (in hexadecimal numbers than binary numbers);
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