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Q&A-KCSE Computer Studies Paper 1

State the uses of 3D printers

  • Making prosthetic limbs for patients
  • Making items which allow precise reconstructive surgery
  • Making light-weight plane wings
  • Making sculptures
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State four data types used in MS Excel

  • Labels
  • Values
  • Formula
  • Functions
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State two data protection rules that should be obeyed by all staff in a hospital.

  • data must be accurate/up-to-date
  • personal data must be registered
  • data must be used for the purpose that is registered for
  • if data is to be used for another purpose the registrar must be notified/
  • subject gives consent
  • patients must be able to see the data and have it changed if it is incorrect
  • processed fairly and lawfully
  • kept no longer than needed
  • kept secure
  • not transferred to other countries without protection
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Describe the difference between a barcode and A quick Response code (QR code)

  • A barcode is one-dimensional while a QR code is two dimensional
  • Barcodes are a set of vertical lines and QR code contains squares
  • QR codes can be read from any angle . Barcode is only above or below and lined up horizontally
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State the name of the storage space used by the operating system when there is insufficient RAM

  • virtual memory
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Describe a typical situation that requires the use of:

(i) a high-level language

(ii) a low-level language.


High level languages are used in situations when:

  1. Speed of execution is not a critical factor, such as in office applications.
  2. a programmer needs to use complex commands that perform complex tasks.
  3. A programmer wants to make use of standardised library / sub routines.

Low level languages are used in situations when:

  1. a program must execute quickly such as real time applications
  2. a programmer needs to write code that interacts directly with the hardware, such as device drivers
  3. a programmer needs to perform a specific command not available in a HL language.
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Describe what is meant by shareware.

 the trial version of software for a limited time/number of uses with limited features  free of charge

If a full version is required need to pay a fee/sign up

When the trial is over user is asked to pay/sign up

Protected by copyright

Type of software licence
 

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State Advantages of online booking

  • It prevents double-booking which could happen in paper-based booking system
  • The customer gets immediate feedback on the availability of seats
  • The customer can make  booking at any time of the day
  • Emails provided by customers during booking can be used by companies for advertisement
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State the reasons for system review and maintenance

  • user changes his mind
  • new government legalisation/company policy company changes
  • changes in hardware
  • changes in software/upgrades/new versions
  • improved operating efficiency/ease of use
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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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What is the difference between a logical file and a physical file?

  • A physical file contains the original data whereas a logical file does not contain any data
  • A physical file contains one record format while a logical file can contain up to 32 record formats
  • A physical file can exist without a logical file while a logical file cannot exist without a physical file
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Outline any 2 Examples of wireless transmission media       (2marks)

  • Radio waves
  • Microwaves
  • Infrared waves
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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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Identify which processor in the PC systems below is likely to process instructions more efficiently. Justify your answer.

  • Processor X: Intel® Core™ i7 processor (3.8 - 5.0 GHz, quad core)
  • Processor Y: Intel® Core™ i5 (2.9 - 4.7GHz, dual core)
  • Processor X is likely to process instructions more efficiently as firstly it has the i7 CPU which is a faster processor as well as the quad core which processes quicker and the higher GHz versus Processor Y
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Differentiate between uploading and downloading a file

Uploading a file  refers to the process of transferring a file from a local computer to a remote webserver while downloading a file refers to the process of transferring or copying a file from a remote webserver to a local machine

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The website has a uniform resource locator (URL).
An example of a URL is given.
https://www.google.co.ke/index.html
Complete the table to identify the name of each section of the URL.

https :  protocol

google.co.ke: domain name

/index.html: webpage/file name

 

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State the factors that affect the performance of the CPU

Number of cores
The number of cores a processor has directly affects the performance of the processor. Each core can perform its own fetch-execute cycle independently of others, so different applications can be allocated to different cores. Quad-core (four-core) and even octa-core (eight-core) processors are becoming common

Cache memory
A processor’s cache is a small portion of incredibly fast memory. It has read and write speeds far higher than hard disk drives and even SSDs. The cache is used to store frequently used information and reduces time wasted in fetching the same information from main memory time and time again

Clock speed
A processor’s clock speed relates to the frequency of the pulses generated by the system clock. The higher the frequency, the more cycles of the fetch-execute cycle can be completed in the same period of time.

Word length
A word is a group of bits that is treated as a single unit by a processor. Words can be used for representing both instructions and data. The length of a word is the number of bits that are assigned to it, with higher word lengths allowing for more bits to be transferred and manipulated as a single unit.

Address bus width
The width of a bus relates to the number wires that make up the bus. Increasing the width of the address bus increases the range of addresses that it can specify, hence increasing the computer’s amount of addressable memory. Adding a single wire doubles the number of addressable memory locations

Data bus width
Increasing the width of the data bus increases the volume of data that can be transferred over the bus at any one time. A wider data bus allows the processor to fetch more data from the main memory in one cycle of the fetch-execute cycle, reducing the number of cycles required to fetch large volumes of data.

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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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Define Domain integrity

Domain integrity - ensures that all data in  a field contain valid values

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Why must operating system be installed in a computer before any other program

  1. Operating system manages the computer hardware thus without it the programs cannot communicate directly to the hardware
  2. Provide a user interface through which a user can give instructions to the computer. Without a user interface, it would be difficult to load or run programs
  3. other programs depend on the operating system to load them into the memory , allocate resources and schedule processor time, Without operating , there would be nothing to co-ordinate the execution of multiples programs
  4. The OS organizes data in files and directories, making it possible for programs to save, retrieve, and modify data.
  5. Without it, programs wouldn’t know where or how to store data.
  6. The OS controls access to files, memory, and devices, ensuring that one program doesn’t interfere with another.


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