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Q&A-KCSE Computer Studies Paper 1

State the functions of the following:

  1. Hub
  2. Router
  3. Switch
  4. Bridge

Bridge: Joins together two networks that use the same base protocols.

Hub: Copies all packets of data to all devices on the network.

Router: Stores the addresses of computers on the network and transfers data between devices.

Switch : Analyses each data packet and sends it to the computer it was intended for.

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Give three features of a data protection act.

  • data shall only be used for the specific purpose for which it was collected
  • data shall be adequate/relevant/not excessive
  • data shall be accurate/up to date
  • data shall not be kept any longer than necessary
  • individuals have the right to see data about them (and have it changed if inaccurate)
  • sufficient means taken for security/integrity of data
  • data shall not be transferred to a country with lower protection laws
  • data users must be registered
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What is repetitive strain injury?

  • the pain felt in muscles, nerves and tendons caused by repetitive movement and overuse.
  • Injury as a result of repetitive use of parts of the body while performing work
  • Strains and injuries due to prolonged typing and use of the mouse
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Give any three advantages of computer networks

  1. Enable resource sharing
  2. Facilitate remote communication
  3. Enable distributed processing
  4. Provide better data security and management

Explain why a developer, who is good at both low-level and high-level programming, would normally use high-level languages when writing programs.

  • High-level languages have built-in functions;
  • High-level languages have built-in libraries;
  • High-level languages have more support/help;
  • High-level languages have structures (such as selection and iteration);
  • High-level languages can be less machine-dependent/more portable;
  • It (usually) requires fewer lines of code to be written;
  • It is (usually) quicker to develop code in high-level languages;
  • It is easier to find mistakes in code;
  • The code is easier to maintain//understand;
  • It is easier to structure code in high-level languages;
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Differentiate between action query and select query

An action query is used to modify, add, or delete data in a database whereas a select query is used to retrieve data from a database based on specified criteria but does not make any changes to the data.

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What characterises a phased implementation approach?

  • Phased means that only one part of the system is implemented at a time
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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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Social engineering is where someone is tricked or manipulated into providing secure information or access to a secure system. Describe each of the following social engineering techniques.

Blagging

  • This is where a victim is tricked/persuaded by a fraudster to give their details or payment information for a false reason/purpose;

Phishing

  • This is where the victim receives and responds to communication that appears to be from a valid or known source but is in fact fraudulent. (It allows the fraudster to capture private information before the victim realises);

Shouldering

  • This is where someone watches and records\remembers a victim entering their pin or security information such as passwords. (They can then use this information to gain access to a system)
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Describe two differences between a switch and a repeater

  • a repeater is a two-port device that amplifies a signal from one port to another
  • a switch is a multiport device that uses a table of addresses to send a signal through the correct port
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What is a computer keyboard?

A computer keyboard is an input device used to enter text, characters, and various commands into a computer or other digital devices.

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Aeroplanes now use Global Positioning Systems (GPS) to determine their location.

Describe how the computer on board the aeroplane uses GPS to find its exact location

Give two benefits of using GPS in this application

Describe how the computer on board the aeroplane uses GPS to find its exact location

satellites transmit signals to onboard computers
computers receive/interpret these signals
system depends on very accurate timing/use of atomic clocks
each satellite transmits data indicating location and time
computer in aeroplane calculates location based on at least three satellites
at least 24 satellites in operation at any one time
position accurate to within one metre
can also calculate altitude of aeroplane
ref to “triangulation”:

Give two benefits of using GPS in this application

safer as the known location is exact/more accurate
reduces the possibility of pilot error
allows accurate estimation of arrival time
display and guide the pilot to the nearest airport in case of emergency

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Describe one difference between system software and application software

  • System software manages the computer hardware/application software
  • application software is for end-user tasks
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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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Give one reason why use of video-conferencing has increased over the last ten years.

– faster communications now widely available
– safety reasons, e.g. increase in terrorist attacks on international flights
– reduced transportation/accommodation/hardware costs
– environmental issues, e.g. reduced carbon footprint
– increase in multinational working

A school opted to use direct changeover approach when installing a new system. Explain three challenges that the school may face as a result of this approach (KCSE 2019)

  • The users may not have gained enough confidence to run the new system
  • It may be very inconveniencing in case the new system fails or faces problems
  • The weaknesses of the old system may not be corrected or may still be transferred to the new system
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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

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KCSE 2016 COMPUTER STUDIES PAPER 1

A manager wishes to replace the current manual system with a computerized one. Describe three areas that must be evaluated to justify the replacement  (6 marks)

  • Technical feasibility
  • Does the current technology suffice
  • Economic feasibility
  • Benefits outweigh costs/ whether the project is cost effective
  • Schedule feasibility
  • Can it be done within the schedule

Headache, back and neck pain may result from the use of computers. State how each of them can be minimized (2mks)

  • Proper lighting
  • Regular breaks
  • Use of antiglare
  • Correct position of the screen
  • Ergonomic furniture

Students of a school intended to elect their school Captain by secret ballot.  State three ways in which computers can be used to improve the election process                           (3mks)

  • Registrations of voters
  • Voter identification
  • Actual voting
  • Tallying
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Explain the functions of the following parts of the CPU

Control Unit; Decodes instruction; Controls the fetching and writing of data;

Arithmetic Logic Unit/ ALU; Executes mathematical instructions;  Executes logical instructions; Compares values held in registers;

 Clock; Controls the number of instructions carried out each second;   allows the CPU to synchronize operations;

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Differentiate between object code and source code

  • Object code refers to a program in machine language while source code to a program in a high level language that must be translated to object code for it to be machine readable
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