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Q&A-KCSE Computer Studies Paper 1

Define the following

(a) Cookies

(b) Spyware

(c) Phishing

(d)Spam

(e) Pharming

 

 

(a) Cookies

  • Information that a website stores about a user on their hard disk; this enables
    the website to remember details about the user when they next visit the website.

(b) Spyware

  • Program installed on a PC to gather information about the user. It monitors
    every key press and relays the information back to the home base

(c) Phishing

  • Sending an email that claims to be from a legitimate company; the recipient is then directed to a bogus website where their personal details will be collected

(d)Spam

  • Junk/ (unsolicited) electronic mail advertising products and services sent to a general mailing list.

(e) Pharming

  • Malicious code installed on a PC or on a server. This code directs users to a
    a fraudulent website without their knowledge.
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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 introduction of a new system involves evaluation and maintenance once the system is
implemented.
Describe the evaluation and maintenance stage of the systems development life cycle (SDLC)
and provide one example of an activity undertaken in this stage.

  • Continually monitoring, evaluating and updating the system once it is operational. Activities include rectifying bugs, requesting changes, updating aspects, finding errors, maintaining code etc.
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Interfaces enable computer users to interact with the operating system.

(a) State four advantages for using a graphical user interface in loading programs and files

(b) A vehicle assembly company has introduced robots to replace the human workforce.  State two effects this would have on the workforce

State four advantages for using a graphical user interface in loading programs and files

  • User friendly
  • No need to know command language as commands are executed by clicking on icons
  • Allows multitasking as several programs open at the same time therefore easier to switch between applications
  • Selecting an item using a mouse is easier and faster than entering commands

Or any other correct response

Advantage @ 1 Mark

Total = 4 X 1 Mark

= 4 Marks

 

A vehicle assembly company has introduced robots to replace the human workforce.  State two effects this would have on the workforce                

  • Unemployment
  • Need to retrain
  • No longer need to do hazardous or tedious jobs
  • Employment of skilled staff who will manipulate the robots

Or any other correct response

Effect @ 1 Mark

Total = 2 X 1 Mark

= 2 Marks

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Describe the query criteria given below

 

(a) Like "*kenya*"

  • Returns the records of all countries that contain the string "kenya"

(b) Like "*ina"

  • Returns records for all countries/regions whose names end in "ina", such as China and Argentina.

(c) Like U*

  • Returns records for all countries/regions whose names start with "U", such as UK, USA, and so on.

(d) Not Like U*

  • Returns records for all countries/regions whose names start with a character other than "U".

(e) >= "Mexico"

  • Returns records of all countries/regions, beginning with Mexico and continuing through the end of the alphabet.

(f) Like "[A-D]*"

  • Returns records for countries/regions whose names start with the letters "A" through "D".

(g) "USA" Or "UK"

  • Returns records for USA and UK.

https://support.microsoft.com/en-us/office/examples-of-query-criteria-3197228c-8684-4552-ac03-aba746fb29d8

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State the symptoms of a computer virus

  1. Slow Performance: If your computer suddenly becomes significantly slower than usual, taking longer to boot up, open applications, or respond to commands, it could be a sign of a virus. Viruses can consume system resources, resulting in decreased performance.

  2. Frequent Crashes: If your computer frequently crashes, freezes, or experiences sudden system reboots without any apparent reason, it could be due to a virus. Some viruses can interfere with system stability, leading to unexpected crashes or instability.

  3. Unusual Pop-ups or Ads: If you start noticing an excessive number of pop-ups, advertisements, or banners appearing on your computer screen, especially when you're not browsing the internet, it might be an indication of adware or malware infection.

  4. Unwanted Modifications: Viruses can modify system settings or configurations without your consent. If you observe changes in your default browser homepage, new toolbars appearing, unfamiliar icons on the desktop, or altered settings, it could be a sign of a virus.

  5. Unusual Network Activity: If you notice excessive network traffic, unusual data transfers, or a sudden increase in data usage without any known reason, it could be an indication of a virus or malware actively communicating with external servers.

  6. Missing or Modified Files: Viruses can delete, encrypt, or modify files on your computer. If you find missing files or encounter unexpected changes in file sizes, names, or extensions, it could be a result of a virus infection.

  7. Disabled Security Software: Some viruses attempt to disable or circumvent antivirus or security software to avoid detection. If you notice that your antivirus program or firewall is deactivated, modified, or unable to update, it could be due to a virus compromising your security software.

  8. Unexpected Email or Message Activity: Viruses can use infected computers to send spam emails or messages to contacts in your address book without your knowledge. If your friends or colleagues report receiving suspicious or unexpected emails or messages from you, it could be a sign of a virus.

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Suggest two advantages of using robots, instead of humans, to build cars in the factory.

  • more efficient than a human
  • more accurate than a human
  • can lift larger and heavier equipment than a human
  • can replace humans working in a dangerous environment
  • reduces running costs, such as wages and overheads
  • can produce consistent results/output
  • can work 24 hours a day // do not need to take breaks.

 

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Describe the purpose of the control unit (CU) within this computer.

  • It sends control signals that manage the transfer of data and instructions within the CPU
  • It decodes an instruction using an instruction set
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State the advantages and disadvantages of the command-line interface

Advantages

  • It is quicker to type commands
  • Little memory needed
  • Little processing power needed

Disadvantages

  • Commands have to be typed precisely
  • There is a large number of commands to be learnt
  • It is not user friendly
  • The user has to remember commands
  • Users cannot transfer data between applications
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A workshop has a lot of heavy machinery operating throughout the day and requires a cable to connect a workstation to a switch. Which of the following, unshielded twisted pair (UTP) or shielded twisted pair (STP) cable, would be the more suitable? Justify your response.

Shielded twisted pair cable:
A twisted pair cable is made up of four pairs of twisted copper wires, a shielded twisted pair cable applies a shield to each one of the pairs on a cable or to all of the pairs together. This shield can reduce EMI (electromagnetic interference), which would be emitted from heavy machinery. This increased data transmission quality in the workshop. STP can also reduce crosstalk.

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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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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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Differentiate between modulation and demodulation as used in data communication

Modulation refers to the process of converting a digital signal to analog signal at the transmission end while demodulation is to converting analog signal to digital signal at the receiving end

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Describe what the traffic control program should do when an emergency occurs.

give uninterrupted path through the system of linked traffic lights/
green link - wave
turn all lights to red
activate emergency generator
alarm

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Below is a labelled diagram of a star topology network.

(a) Other than the items labelled above state the hardware required by every computer to connect to a network

b) Describe how a packet is transmitted from computer A to computer D, including the role of the switch

 

(a)

  • Hardware required by each computer to connect to a network is a Network Interface Card / NIC / network adapter

(b)

  • Computer A adds computer D’s address to packet
  • Computer A sends packet to switch
  • Switch looks at address on packet  Switch compares to stored list of addresses on network
  • Switch forwards packet to computer D’s address
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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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List three characteristics of Internet Protocol version 6 (IP6).

  • has a significantly larger address pool than previous version
  • features a client-side address assignment
  • has built-in encryption
  • enables one device to have many network addresses
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Define programming
The process of developing computer programs to solve a particular problem
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Identify four different types of computer network.

  1. MAN
  2. WAN
  3. PAN
  4. LAN
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List two areas where infrared waves are used in data communication.

TV remote, wireless mouse , wireless keyboard, used by robots to gauge distance and avoid obstacles,

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