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Q&A-KCSE Computer Studies Paper 1

Distinguish between firmware and device drivers as used in computers.                  (2mrks)

  • Firmware is a software program permanently etched into a hardware device such as a keyboards, hard drive, BIOS, or video cards.
  • Device drivers are operating system-specific and hardware-dependent. A device driver acts as a translator between the hardware device and the programs or operating systems that use it. 
  • Firmware is a software that controls a system, and firmware's functionality ranges from performing basic tasks like minimal I/O controls to full-fledged software system running with simple or no OS, with scheduler, memory management, etc. 
  • driver, on the other hand, is usually part of the operating system that performs the specific task of controlling a hardware component like a display or USB controller, etc., and gives an interface to use the hardware by Operating system and applications.
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State the functions of the following utility programs

(a) Defragmentation software

(b) Disk contents analysis/repair software

(c) Disk formatter

(a) Defragmentation software   -   Reorganises files on a disk to improve efficiency

(b) Disk contents analysis/repair software - Scans a hard disk to identify bad sectors

(c) Disk formatter -  Prepares a hard disk for first 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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State email protocols

  • Simple Mail Transfer Protocol (SMTP)
  • Post Office Protocol (POP)
  • Internet Message Access Protocol(IMAP)
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Describe the role of the registers and system clock within the fetch-execute cycle.

  • Registers are small amounts of memory available that hold data fetched from memory or data waiting to be stored in memory. A temporary holding place for the instruction that has been fetched.
  • The system clock purpose is to determine the pace of the cycle, each tick of the clock a part of the fetch-execute cycle occurs. Regulates the timing and speed of a computers systems functions.
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Define programming
The process of developing computer programs to solve a particular problem
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state two advantages of using a pseudocode during program design

  1. Speeds up coding since converting a pseudocode into a programming language is usually faster and easier
  2. Acts as documentation
  3. Simplifies debugging since logical errors can be identified and corrected early in design stage
  4. Language independent since it is not tied to any specific language so can be translated into different languages
  5. It uses simple english-like statements
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State the areas where infra-red radio waves are used      KCSE 2018

  • TV remote control communication;
  • DVD remote communication
  • Communication between peripheral devices and the computer
  • Data link over a short distance using mobile phones Radio remote control
  • Remote locking/opening doors/ devices
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(b) Routers have an important role in how the internet functions.
  Describe how a router directs data on the internet.

  • Reads the data/packet to find the recipient's address 
  • Has physical connections to >=2 different networks
  • Holds a routing table
  • Stores information about (IP) addresses 
  • Keeps packets inside a network by not forwarding them 
  • Forwards data / directs/forwards/sends packets 
  • Chooses the most efficient path to the next node
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Name three of the stages in the system life cycle

fact finding
feasibility study
analysis
design
testing
documentation
implementation/changeover/installation
evaluation
maintenance

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State the function of a router in a network

  • connects different networks
  • transfer data packets from source to destination
  • allow hosts on different networks to communicate
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Using an example, explain a difference between a primary key and a foreign key in a relational database.

A primary key is a table field that uniquely identifies each record and ensures that duplicate entries are not allowed

A foreign key is primary key of a parent table placed in a child table to ensure that any record added to a child table is related to the one in parent table.


A foreign key is a field (or a set of fields) in one table that refers to the primary key of another table. It is used to establish and enforce a link between the data in the two tables, ensuring referential integrity.

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A school has 3000 students sitting final examinations.

Each student sits eight examinations.

Write an algorithm, using pseudocode or a flowchart, which:

inputs the marks for all 8 examinations for each student

outputs for each student the average mark for their 8 examinations

outputs the highest mark overall

highest = -1
for student = 1 to 3000
total = 0
for exam = 1 to 8
input mark
total = total + mark
if mark > highest then highest = mark
next
average = total/8
output average
next
output highest

Python code:

highest = -1
for student in range(1, 3001):
    total = 0
    for exam in range(1, 9):
        mark = int(input("Enter mark: "))
        total += mark
        if mark > highest:
            highest = mark
    average = total / 8
    print("Average:", average)
print("Highest mark:", highest)

VBA Code

Option Explicit

Sub CalculateAverageAndHighest()
    Dim highest As Integer
    Dim total As Integer
    Dim mark As Integer
    Dim average As Double
    
    highest = -1
    
    For student = 1 To 3000
        total = 0
        For exam = 1 To 8
            mark = InputBox("Enter mark:")
            total = total + mark
            If mark > highest Then
                highest = mark
            End If
        Next exam
        average = total / 8
        MsgBox "Average: " & average
    Next student
    
    MsgBox "Highest mark: " & highest
End Sub

 

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Computer Studies Paper 1 2021  KCSE Prediction Section B Qs. 17,18 and 19

17. a) i) Explain the term search as used in the Internet.                                            [2]

A web based application that locates items or information from the World Wide Web

ii) Peter intends to download a movie from the Internet. State the three factors that may determine the total time taken to complete the download.                                           [3]

  • Size of the video/format
  • The bandwidth of the media/speed of network/network traffic
  • Type of browser software
  • Background activities running in the computer
  • Restrictions enforced in the computer/firewall/antivirus
  • Speed of the computer/CPU speed
  • Size of RAM

b) Wakulima online is an organization that runs a web based system for assisting farmers to obtain market for their produce. State four technological reasons that may cause a farmer not to access the organization’s system.                                                                                  [4]

  • Poor network/lack of connection
  • Software failure in the system
  • Hardware failure
  • Lack of access rights
  • System overload/hanging
  • Lack of skills/disability/illiteracy
  • Lack of power supply

c) Explain a situation when each of the following Desktop Publishing program features may be used when creating a publication:

i. Cropping                                                                                                               [2]

Applies to graphics – used to trim/remove/hide some portions in the graphics

ii. Transparency                                                                                                         [2]

Used to make background of a graphic to be clear/visible

d. List two areas where infrared waves are used in data communication.                             [2]

18. a) List four activities of the planning stage of systems development.                             Ignore this question, marks redistributed elsewhere

b) Explain a circumstance when each of the following feasibility studies are carried out during systems development.

i. Technical                                                                                                               [3]

Done to determine whether technology exists to support the proposed solution

 

ii. Economic                                                                                                              [3]

Done to determine whether the proposed solution is economically viable

 

iii. Schedule                                                                                                               [3]

Done to determine whether the proposed system can be done within an acceptable time.

c) Table 1 and Table 2 are related tables in a database. Use them to answer the questions that follow.

Table 1

Dept Code

Dept Name

001

Computer

002

Aviation

003

Engineering

 

Table 2

DeptID

Student Registration No.

Student’s Name

002

St01

Alex Too

003

St02

Naomi Komi

002

St03

Peter Kengo

 

i. Identify the appropriate primary key for each table.                    [2]

Table 1 – Dept code, Student Registration No

ii. Explain two benefits of enforcing referential integrity in the database. [4]

  • No record can be added in Table 2 if its corresponding record in Table 1 does not exist
  • No record in Table 1 can be deleted without first deleting the corresponding record in Table 2
  • Reduces data redundancies/ensures integrity
  • Prevents deletion of related table

19. a) Describe each of the following validation checks as used in data processing.

i. Preserve check                                                                                                      [2]

Ignore this question, marks redistributed elsewhere

ii. Data type check                                                                                                    [2]

Ensure correct type of data is entered for the field

iii. Check digit                                                                                                           [2]

This is a number added/calculated by the computer to a binary number. The check digit ensures correct transmission of the binary number.

b. Write each of the following abbreviations in full:

i) BCD                                                                                                                                    [1½]

Binary Coded Decimal

ii) EBCD                                                                                                                                 [

This question was thrown out and marks redistributed elsewhere

iii) ASCII                                                                                                                    [1½]

American Standard Code for Information Interchange

c) Using 10-bits binary number system, perform the following decimal operation using two’s complement.                                                                                                                                   [6]

12910 - 12810

+129 = 00 1000 0001

128 = 00 1000 0000

-128 = 11 0111 1111 (ones complement)

                            +1

          11 1000 0000 (Twos complement)

129- 128

     00 1000 0001

+ 11 1000 0000

 100 0000 0001

Hence = 00 0000 00012 or 12 (the overflow bit is ignored)

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The Acme company stores data for a private scientific research group. It has recently upgraded its storage capacity and needs to dispose of its existing hard drives securely. Outline two methods for the secure disposal of the data on the hard drives.

Acme company needs to ensure that if they are reselling the drives they wipe the drive (this should be done regardless of the destruction of the drive) to the DoD standard.

  • Disassemble the drive by pulling it apart the drive so that the data would not be accessed
  • Destroy the metal disk either by drilling holes so it cannot be read
  •  Encrypt drives with passwords that are not accessible
  • Degaussing the hard drives
  • Use specialized overwriting software

This would ensure that any software cannot be used to locate files.

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Suggest one disadvantage to the programmer of using a high-level language instead of a low-level language.

  • not able to directly manipulate the hardware
  • may need to wait for translation before running
  • the program may be less efficient.

 

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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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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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List two primary functions of a domain name server.

  •  map IP addresses to names and criteria
  • To map directory services
  • Maintain directory of domain names
  • To map URL (web address) to IP address
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Differentiate between Physical and logical topologies

  • Physical topology deals with the placement of nodes
  • Logical topology deals with the data flow  in the network
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