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Q&A-KCSE Computer Studies Paper 1

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

State four data types used in MS Excel

  • Labels
  • Values
  • Formula
  • Functions

State the difference between radio waves and microwave transmission

  • Radiowaves are omnidirectional while microwaves propagate in one direction at a time(unidirectional)
  • Radiowaves can be propagated over long distances through sky mode while microwaves require a relay satellite to amplify and retransmit the microwaves signals to the receiver earth station

List two types of disaster recovery tools.

  • online storage
  • incremental backup
  • full backup
  • RAID (level 0, 1, 10)
  • uninterruptible power supply (UPS)

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?

Describe the purpose of two registers that are used by Von Neumann architecture.

MAR( memory address register)

  • Stores the address/location where data will be read/written/accessed/fetched
  • stores address/location of data/instruction being processed
  • stores address/location of data/instruction next to be processed

MDR or  memory data register

  • Stores the data/instruction that is fetched/read from memory
  • stores the data that is to be written to memory
  • stores the data/instruction from the address in the MAR
  • stores data/instruction next to be processed

 Program counter

  • Stores the address/location of the next instruction to be run
  • stores the address/location of the current instruction being run

Accumulator

  • Stores the result of manipulation/process/calculation

What is a web browser?

  • A software which can display a webpage on a user's computer screen

Describe two desirable features to look for in a laptop rather than a desktop computer.

– lightweight
– long battery life
– cool running processor
– touch pad
– internal webcam

Describe how the database can be recovered from a system failure

  • backups/dumps of files
  • copy of files on CD/tape streamer
  • file generations

Apart from the user interface, name three other components that make up a typical expert system.

– knowledge base
– rule(s) base
– inference engine
– explanation system
– (expert system) shell

State the primary function of the Dynamic Host Configuration Protocol (DHCP) protocol.

  • it generates and/or allocates an IP address

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

A car park uses a number plate recognition system. Identify the reason why unsigned integers should be used to record the number of cars entering and leaving the car park, rather than signed integers

  • Unsigned integers store more positive values

Distinguish between microwave and a radiowave transmission and a microwave transmission  (KCSE 2017 PP1)

Microwaves can cover shorter distances. On the contrary, radio waves can travel a long distance. Radio wave is usually propagated through sky mode while microwave uses the line of sight propagation. 

Explain one reason why a computer needs to be connected to a stable power source

System Stability: Computers require a consistent and stable power supply to function properly. Fluctuations or interruptions in the power source can cause various issues that can disrupt the computer's operation or lead to hardware damage.

a. Data Loss: Sudden power outages or voltage fluctuations can cause the computer to shut down abruptly, resulting in data loss if unsaved work is not properly stored. This can be particularly problematic when working on critical tasks or handling important files.

b. Hardware Damage: Power surges or inconsistent power supply can damage the computer's internal components, including the motherboard, CPU, memory, and storage devices. These damages can result in system instability, reduced performance, or even complete hardware failure.

c. Operating System Corruption: Abrupt power loss or inconsistent power supply can corrupt the operating system files, leading to system crashes, error messages, and instability. This may require system repairs or reinstallation of the operating system.

d. Component Lifespan: Inconsistent power supply can put unnecessary stress on computer components, shortening their lifespan. Frequent power fluctuations or surges can cause wear and tear on various parts, reducing their efficiency and overall longevity.

What situations are likely to call for the use of Direct Changed Over?

  • where the new system is completely different from the old one
  • if there has been extensive testing of the system and the system analyst has confidence in its functionality
  • If the system is not critical

In reference to word processing, define the following terms

Word wrap

Justification

Drop cap

Word wrap - Is a word processing feature in which a word that does not fit in the current line is automatically moved at the start of the next line

Justification - refers to aligning text on both left and right margins

Drop cap - Make the first character of a paragraph occupy more than one line below it

Give two reasons why some microprocessor controlled devices do not require an operating system

  • They run only one program/task
  • OS would increase development and manufacturing cost as more storage will be needed

Describe why fibre optic cable would be used for the backbone of the network. (2 marks)

 

Describe how the firewalls can ensure the security of the EmergWA network.

 

Describe a transmission media that would work better in remote areas

The volunteers assisting in an emergency all wear personal protection equipment (PPE) that has an RFID tag sewn into the collar so that they can be tracked if they become lost in a remote location. Identify what RFID is and outline how it works. (3 marks)

  • Fibre optic cable would be used because it has a higher bandwidth, allowing faster communication in the main part of the network. It is also more secure as it cannot be tapped.
  • Firewalls filter the data in and out of a network. Each packet is examined against the filter rules and if a packet is flagged, it is dropped. Only data packets that satisfy the filter rules are allowed through the firewall, thus providing a layer of security for the network.
  • A satellite system would be better as it does not rely on wifi, cellular etc. It is not subject to interference and is reliable in remote conditions
  • Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to track inventory goods..

Differentiate between a function parameter and a function argument

A parameter represents additional information that  a function requires to perform its task. Each parameter required by a function is specified in the function header

An argument the value supplied in the function call. When the function is called, the argument value is passed into the function parameter so that the function can perform its task