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Q&A-KCSE Computer Studies Paper 1

Describe what is meant by a clock speed of 3.8 GHz.

  • The number of FDE cycles run per given time/second
  • the frequency that the clock ‘ticks’
  • 3.8 billion cycles/instructions per second
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Identify four events that take place during the fetch-execute cycle

  • An instruction is retrieved from the memory
  • The instruction is decoded
  • The instruction is executed
  • the program counter is incremented
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Define the term multimedia

  • Is an integration of sound, text, graphics, and video to convey information
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Distinguish between transcription and transposition types of errors and give an example of each  (4mks)

Transcription Errors: Transcription errors involve the incorrect entry of data due to mistakes made during the copying or typing process. These errors can occur when transferring information from one source to another.

Transposition Errors: Transposition errors specifically refer to errors where the order of characters or digits is accidentally reversed or swapped. This can happen during manual data entry or when processing information.

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State two reasons why the data in fields such SEX field in a database should be coded.

  • less errors on input
  • requires less storage space
  • validation
  • quicker to input
  • quicker to find
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5 Artificial intelligence is an emerging trend in computer science.
(a) Discuss the use of artificial intelligence by describing some of its characteristics, the ways in which it may be used and the ethical issues associated with its use.
 

Branch of computer science based on enabling computers to
behave like humans/mimic aspects of human intelligence
AI is implemented in software.
Combines psychology, biology, linguistics, mathematics, neuroscience,
and philosophy (ethics)
AI is not the same as the general intelligence of human beings

 

Uses – Any of the following:
Game playing (chess, quiz, video games)
Analytics (analyse buying patterns, predicting behaviours, predictive
text, financial markets)
Image processing (recognising objects/patterns)
Logistics (scheduling, order fulfilment)
Control systems (cars, manufacturing, weapons, navigation)
Expert systems (medical, mechanical, electrical diagnosis)
Neural networks (simulating neuron behaviours as in brains)
Natural languages processing (chatterbots, chatbots, speech
recognition)
Robotics (dangerous situations, help aged or disabled)

 

Ethical issues – Any of the following:
Take the work of humans, thereby affecting employment rates
Is a computer to be trusted to make decisions (life-death)?

If a computer discovers something that humans can’t prove, should it be
accepted as truth?
Do AI machines have rights?
Will people be comfortable interacting with machines that are
considered intelligent?

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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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Give an example of where a PAN could be used

  • connecting wireless headphone to a phone
  • Using a wireless mouse, keyboard etc
  •  
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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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Describe the following threats to privacy and confidentiality: Eavesdropping, surveillance and industrial espionage
Eavesdropping refers to tapping or listening into communacation channels to get information. According to study.com, it is defined the unauthorized interception of a conversation, communication or digital transmission in real time study.com
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A large comprehensive school has over 500 computers connected to their Local Area Network (LAN) with a connection to the Internet. (a) Describe, in detail, four disadvantages for the school of having a network of computers compared to stand alone computers

 A network manager may need to be employed  which might be expensive

Could be infected with a virus that could spread to all other computers

Security problems receive traffic from other networks

Hackers may gain access as the network only as secure as weakest point of entry to data and steal/destroy

 The server/switch could go down (main cable break) so all workstations on the network are affected

 Can be expensive to set up as Initial cost of servers, communication devices, switches, network software etc. 

 Substantial Initial disruption: drilling holes, fitting trunking, running cables between buildings etc… 

 Can have a slow response time  due to heavy network traffic so users cannot work as effectively

 Detecting network problems can be more difficult on a network i.e difficult to isolate

 Can be slow to log in to a network  As it slow to download software/check password

 Only limited storage space available on network while one has access to all hard disc drive on standalone computer

 Time and effort to set up users o Can just start a standalone and use computer

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For your item named in (a) describe two different tasks that the microprocessor performs.

  • camera film speed, position (end of film), distance, light
  • washing machine amount of water, speed of wash/temperature/time
  • fridge temperature, display panel
  • air conditioning temperature, timing, display pane
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A computer is upgraded to a dual-core CPU.
Explain how the upgrade can affect the performance of the computer.

  • It can now process two instructions simultaneously (where suitable) increasing the performance.

 

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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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Ochieng manages a network for an organisation.
(a) Two computers are assigned the same IP address.
Explain why Ochieng must change the IP address of one of the computers.

  • Devices must have a unique IP address because otherwise, a switch would not know which of the two was the correct device to send packets to

(b) Identify the network topology that requires a server.

  • Star topology

Ochieng manages a network for an organisation.
(a) Two computers are assigned the same IP address.
Explain why Ochieng must change the IP address of one of the computers.

  • Devices must have a unique IP address because otherwise, a switch would not know which of the two was the correct device to send packets to

(b) Identify the network topology that requires a server.

  • Star topology
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A school intends to install a computer network. Explain three challenges that the school may experience after the installation (KCSE 2021 Computer Studies Q19(b))

Network Failure - when the network becomes faulty or the network is down, users may not access network resources hence operations of an organization may be brought to a standstill

Security Issues:  A computer network can be accessed thus there is an increased chance of hacking

The rapid spread of viruses: Viruses can easily spread to terminals of a computer network which may be very expensive to clear

Cultural and moral effects: adult content may be shared in a networked environment which may be of negative impact on teenagers

 

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Outline a factor that can influence the performance of a network.

  • The different factors that can influence the performance of a network include: bandwidth, network design, data collisions, and excess broadcast traffic.
  • The bandwidth can influence through the method of transmission and medium used
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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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What is block operation as used in Microsoft word?

An editing or formatting procedure that is carried out on a selected block of text in a word-processing document.

A formatting or editing operation that is applied to a block of text after selecting. The block of text can be a paragraph, line, word, page or the whole document. It is much easier to apply editing or formatting to a block of text than to apply it to every single character

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Ahmed uses the Internet for some time and is puzzled by the terminology.
(a) Draw a line to match each description to the appropriate technical term.

  • a computer that responds to requests to provide information and services over the Internet - an Internet server
  • defines how messages are transmitted and formatted over the Internet-HTTP
  • software that enables users to access/view documents and other resources on the Internet - Browser     
  • numerical ID for each device on the Internet-IP address
  • unique ID for a network interface card  -MAC address
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