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Q&A-KCSE Computer Studies Paper 1

Give two uses of spreadsheets in a government office concerned with carrying out national census
Tallying population size Establishing demographic trends Drawing pie charts to show population share by gender Doing census budgets

State three factors to consider when selecting an operating system to install in a computer        (3 marks)

  • Ease of installation and use
  • Application software intended for use in the computer
  • Processor type. Some processors do not support all operating systems
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Shaneela is designing and coding a website. The files she creates will be stored on
a computer.
(a) File management is a function that an operating system performs.
Describe how an operating system organises files

The organisation of files is in a hierarchy/tree structure
A node is either a folder/directory/sub-folder/sub-directory or the file itself
The top node/folder/directory/drive is the root

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The Unicode character set is used to represent text that is typed into a computer.
(a) Describe what is meant by a character set.

(b) One disadvantage of using the Unicode character set, instead of the ASCII character set, is
that the text stored takes up more storage space.

  • All the characters and symbols that can be represented by a computer system.
  • Each character and symbol is assigned a unique value.

(b) One disadvantage of using the Unicode character set, instead of the ASCII character set, is

that the text stored takes up more storage space

  • Each character is encoded using more bits

 

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Give one difference between a compiled program and interpreted program

  • A compiled program will only execute on a processor of specific type/family/with same instruction set
  • A program run using an interpreter can execute on a computer with any type of processor;
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Define Data Security

  • Is the protection of programs and data in computers and communications systems against unauthorized modification, access or disclosure
  •  
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Jane has noticed the following problems with her computer  (2mks)

  • It is taking a longer time to start up;
  • It is often hanging;
  • Applications are taking longer to load.

State three possible causes of these problems and how they can be solved (3mks)

There could be several possible causes for the issues Jane is experiencing with her computer keyboard, including:

1. Software Issues
   - Cause: Outdated or corrupt system files, drivers, or operating system.
   - Solution:
     - Ensure the operating system and drivers are up-to-date.
     - Run a system file checker to repair any corrupted system files (e.g., on Windows, run "sfc /scannow" from the Command Prompt).
     - Consider reinstalling the operating system if issues persist.

2. Hardware Issues:
   - Cause: Physical damage or malfunction in the keyboard hardware.
   - Solution:
     - Check for physical damage or debris under the keys and clean the keyboard if necessary.
     - If cleaning doesn't help, consider replacing the keyboard with a new one.

3. Resource Overload:
   - Cause: The computer may be running too many background processes or lacking sufficient hardware resources.
   - Solution:
     - Close unnecessary background applications and processes to free up system resources.
     - Consider upgrading the computer's RAM, CPU, or storage if it's outdated and unable to handle current software demands.
     - Use task manager or activity monitor to identify and terminate resource-intensive processes.

4. Malware or Viruses:
   - Cause: Malicious software can slow down a computer, cause hanging, and delay startup.
   - Solution:
     - Perform a full system scan using reputable antivirus or anti-malware software to remove any threats.
     - Ensure that the operating system's security patches are up-to-date.

5. Disk Fragmentation:
   - Cause: Fragmented files can slow down the loading of applications and overall system performance.
   - Solution:
     - Run a disk defragmentation tool (e.g., Windows' built-in tool) to optimize file storage on the hard drive.
     - Consider upgrading to a solid-state drive (SSD) for faster application loading times.

6. Insufficient Storage:
   - Cause: If the hard drive is nearly full, it can cause slow performance.
   - Solution:
     - Free up space by deleting unnecessary files and programs.
     - Consider upgrading to a larger capacity hard drive or SSD if storage space remains an issue.

7. Background Processes and Startup Items:
   - Cause: Too many unnecessary programs running in the background or starting up with the computer.
   - Solution:
     - Disable or remove unnecessary startup items and background processes to improve startup time.
     - Use the Task Manager or System Preferences (on macOS) to manage startup items.

It's important to diagnose the specific cause of the issues Jane is facing by troubleshooting each potential problem one by one. In some cases, a combination of these solutions may be necessary to fully resolve the problems with her computer keyboard.

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Name two other input/output devices used at the POS terminal apart from keyboard and barcode reader and give a use for each device.

device: beeper/loud speaker
use: to indicate barcode correctly read/error in reading barcode
device: (LCD) screen/monitor
use: to show prices and other information about goods
device: touch screen
use: to show prices and other information about goods/to select items that need to be
weighed/identified
device: weighing machine
use: to find weight of loose items (e.g. fruit) to enable pricing
device: (magnetic) card reader/CHIP and PIN reader
use: to read customer’s debit/credit card/enable customer to pay for goods using a
credit or debit card
device: printer
use: to print receipts

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Students are using their wireless notebooks to complete their work in a classroom. They will need to connect wirelessly to a printer to print their answers at the end of the lesson.
Describe how CSMA/CA (Carrier-sense multiple access with collision avoidance) operates in the above scenario.

  • All nodes ‘listen’ for traffic to sense when the network is idle.
  • When a node wishes to transmit, it transmits a ‘request to send’ frame’ (RTS)
  • The intended receiving device will transmit a ‘clear to send’ (CTS) frame if it is available.
  • All other nodes ‘sense’ the network is busy and wait a random amount of time before trying to transmit
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Aeroplanes now use Global Positioning Systems (GPS) to determine their location.

Describe how the computer on board the aeroplane uses GPS to find its exact location

Give two benefits of using GPS in this application

Describe how the computer on board the aeroplane uses GPS to find its exact location

satellites transmit signals to onboard computers
computers receive/interpret these signals
system depends on very accurate timing/use of atomic clocks
each satellite transmits data indicating location and time
computer in aeroplane calculates location based on at least three satellites
at least 24 satellites in operation at any one time
position accurate to within one metre
can also calculate altitude of aeroplane
ref to “triangulation”:

Give two benefits of using GPS in this application

safer as the known location is exact/more accurate
reduces the possibility of pilot error
allows accurate estimation of arrival time
display and guide the pilot to the nearest airport in case of emergency

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Name three types of cables used in data communication

Twisted pair cables

Coaxial cables

Fibre optic cables

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A school opted to use direct changeover approach when installing a new system. Explain three challenges that the school may face as a result of this approach (KCSE 2019)

  • The users may not have gained enough confidence to run the new system
  • It may be very inconveniencing in case the new system fails or faces problems
  • The weaknesses of the old system may not be corrected or may still be transferred to the new system
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State two advantages of electronic databases over a flat file

  • Data Integrity: they provide ways or mechanisms for enforcing data integrity constraints, such as referential integrity. If a record in the parent table is deleted, related records in the child table also get deleted. This ensures accurthe acy and consistency of data stored in the database
  • Data Security
  • Concurrency control
  • Reduces data redundancy
  • Data retrieval and querying
  • Data indexing
  • Data consistency and acid transaction
  • Data backup and recovery
  • Data sharing and collaboration
  • Convenient data maintenance
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Describe overtype and insert modes as used in word processors

  • Overtype mode: deletes the current text at the cursor position and replaces the existing characters with new text
  • Insert Mode: pushes the existing text away as new text is inserted between the existing text
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Outline one advantage and one disadvantage of interviews and questionnaires as data gathering techniques.
 

Interviews

Advantages

  • can gather specific information and additional information
  • high response rate to questions
  • The question can be rephrased to seek more clarification
  • it is possible to win the confidence of the interviewee and get honest answers

Disadvantages

  • time consuming
  • responses to interview questions are subjective.
  • the interviewee may not open up on some sensitive issues
  •  

Questionnaire

Advantages

  • easy to administer
  • can be anonymous.

Disadvantages

  • fixed (inflexible) design
  • potential differences in understanding and interpretation.
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State two reasons for carrying out software updates

  • To get the latest features
  • To update security features
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State the contents of a feasibility study report

  • Recommendation on whether to continue or abandon the project
  • Methods used to collect data
  • benefits and limitations expected
  • the technology required to develop and maintain the project
  • Installation and running cost
  • Time limit
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State two places where robots are used.

  • car factories/factories
  • chemical/nuclear factories
  • production lines
  • warehouses
  • deep in the ocean/down mines
  • on other planets/in space
  • road junctions

Describe three possible threats to the computers connected to the network and give one way each threat can be reduced or prevented

Virus / trojan / worm / malware

  • Piece of software/code/a program that replicates itself  or causes damage e.g. editing/deleting files

Prevention

  • Running anti-virus/anti-malware software 
  • don’t download from unknown sources
  • don’t click on unknown links

Spyware / malware / keylogger

  • Piece of software/code/a program that records actions/key presses and sends this data to a third party analysis

Prevention

  •  Running anti-spyware/anti-malware software/firewall

Data interception / passive

  • Data is sent to another device and is intercepted by a third party

Prevention

  • Encryption

Phishing

  • An e-mail has a link that when clicked directs the user to a fake website that collects personal data

Prevention

  • Network policy // firewall

Pharming

  • A piece of code installed that redirects user to fake website that collects personal data

Prevention

  • Anti-malware or firewall

Hacker

  • Person attempting to gain unauthorised access to the network/computers/ data/files 
  • unauthorised access and then deleting/editing data/files

Prevention

  • Firewall
  • strong password 
  • biometrics
  • penetration testing
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451/1

COMPUTER STUDIES

PAPER 1

THEORY

DECEMBER 2021

TIME: 2 HOURS

 

FORM TWO END OF TERM TWO 2O21 EXAM

451/1

COMPUTER STUDIES

PAPER 1

THEORY

TIME: 2½ HOURS

 

INSTRUCTIONS TO CANDIDATES:

  • Write your name and ADMISSION number in the spaces provided above.
  • Write the date of examination and sign in the spaces provided.
  • This paper consists of two sections.
  • Answer all the questions in section A.
  • Choose one topic to answer in section B
  • All answers must be written in the spaces provided in this question paper.
  1. SECTION A
  2.  Answer all questions in this section
  3. What is a computer?                                                                                                            1mks
  4. State three physical components that make up a computer                                                 3mks
  5. State the hardware technological differences between the second generation and third generation computers                                                                                                          2mks
  6. State and explain three characteristics of a computer                                                         3mks
  7. State the functions of the following special memories in a computer                                3mks
  8. Buffers
  9.  
  10. Registers
  11. Cache
  12.  
  13. Define the following as used in data representation in a computer                                  (5mks)
  14. Bit
  15.  
  16.  
  17. Byte
  18.  
  19.  
  20. Nibble
  21.  
  22.  
  23.  
  24. Word
  25.  
  26.  
  27.  
  28. Word-length
  29.  
  30.  
  31. State two reasons why a DVD is superior to a typical compact disk                               (2mks)
  32. State three advantages of flat panel monitors over cathode ray tube monitors                   3mks
  33. Explain the following terms as used in word processing                                                  3mks
  34. Section breaks
  35. Thesaurus
  36. Superscript
  37. State two advantages of  impact printers                                                                             2mks
  38. State the function of the following keys on the computer keyboard                                  3mks
  39. Enter key
  40. Insert key
  41. Delete key
  42. State the technology used by the following secondary devices to store data                      3mks
  43. Magnetic storage devices
  44. Solid state storage devices
  45. Optical storage devices
  46. State three reasons why an operating system is important in a computer                         3mks
  47. A typical computer’s main memory consists of both volatile and non-volatile memory.
  48. i)  Explain what is meant by the term volatile memory                                          (1mark)
  49. ii) What is normally stored in the non-volatile part of a computer’s main memory (1mark)
  50. Explain why having cache memory can improve the performance of the CPU         (2mks)
  51. What is a computer system?                                                                                           (1mk
  52. Give two differences between a solid state drive (SSD) and a hard disk drive (HDD)   2mks
  53. State three categories of software classified according User license agreement              (3mks)
  54. State two disadvantages of Random Access Memory                                                       (1mk)
  55.  
  56.  
  57. a) Explain the functions performed by the following components of a processor   (2 marks)
  58. Control unit
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