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Q&A-KCSE Computer Studies Paper 1

State and explain four network communication devices

  • Repeaters : amplify data signal thereby extending the physical coverage of a network. It can connect two LANs locally.
  • Bridges: connect similar types of networks e.g a token ring to another token ring
  • Routers: link networks of different types
  • Gateway: allows computers in a network to connect regardless of their topology
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(iii) John von Neumann proposed the concept of a stored program.
   State the two items he proposed to store in main memory.

 Data

Instructions

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State two functions of utility software

  • Repairing files
  • Compression
  • Defragmentation
  • Back up
  • Anti-virus / anti-spyware / anti-malware
  • Firewall
  • Managing application updates
  • Format disks/drives
  • System analysis tools
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Joelle’s parent also uses the firewall to limit the websites that Joelle can access.
Explain how the firewall is used to limit the websites that Joelle can access

(The parent can) set criteria for the websites she is allowed to visit such as a whitelist/blacklist of websites. The firewall will examine the data/traffic incoming and outgoing from her computer. If data is sent from a website that is not allowed, it will be blocked

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What is an information system ?  (KCSE 2012))

Is an arrangement of people, data, processes, communication and IT that interact to support problem solving

 

Components of an information system

  • Hardware
  • Software
  • Data - information manipulated by software
  • people- all people involved
  • Processes - steps to accomplish a goal
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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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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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What is entity integrity?

  • It ensures that each row has a unique and non-null primary key
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State the functions of the following features in word processors

  • Thesaurus - Is a feature in a word processor that suggest words with the similar or opposite meaning to the one selected
  • Comments: a feature in a word processor that allows a user to attach a remark about the selection
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Satellite services are used to provide broadband internet connectivity to regional and remote areas of Kenya. State one advantage and one disadvantage of using satellites for this purpose.

Advantages

  • can cover large areas
  • requires minimal land-based transmission support
  • requires minimal infrastructure to provide internet access
  • minimal impact on the environment or humans.

Disadvantages

  • transmission speeds are not comparable with other forms of transmission
  • data costs are expensive by comparison to other forms of transmission
  • expensive to deliver.
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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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Explain the difference between how the IMAP (Internet message access protocol) and SMTP (simple mail transfer protocol) protocols are used

IMAP

  • Retrieves/accesses/downloads (a copy of an) e-mail
  • Allows synchronisation/management of account

SMTP:

  • Sends/forwards/transmits e-mai
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When an image is inserted in a DTP document is selected, handles on its placeholders appear.  State three uses of these handles

  • Used to resize the image
  • Used to rotate the image
  • Used to move the image
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Describe the role of a repeater when used in a network.

a repeater will amplify a signal and resend it to overcome reduction in signal strength (attenuation) because over a distance network signals diminish in size/amplitude (are attenuated) due to characteristics of the media.

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(ii) State what ROM and RAM store.

 

ROM stores BIOS / bootstrap / start-up 

RAM stores currently executing programs and data

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Differentiate between bus topology and star topology of networks. What are the advantages and disadvantages of star topology over bus topology

  • Bus topology is characterised by common transmission media shared by all the connected nodes
  • Star topology is characterised by a central switching node connected directly to each of the multiple nodes in the network

Advantages of Star topology over Bus topology

  • Faster communication as compared to bus topology
  • Independent line of connection allows freedom of removing or adding nodes

Disadvantages of Star topology over Bus topology

  • Expensive as compared to the bus topology
  • Long cable length
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Explain a situation when each of the following Desktop Publishing programs features may be used when creating a document

(i) Crop - used when handling a graphic and there is a need to remove some of the portions in the graphic

(ii)Transparency - used when there is a need to make background of a graphic visible

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Describe how the CPU and main memory work together.

Data and instructions are fetched from main memory, from addresses requested by the CPU on the address bus. (Data and instructions are sent) using the data bus. (Data and instructions are then) decoded and executed in the CPU.
Results of operations are sent back to the memory on the data bus

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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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