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Q&A-KCSE Computer Studies Paper 1

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..
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(ii) The organisation has chosen wireless connectivity over wired connectivity for its new office building. There is no significant difference in the cost of installing either.
Give three reasons why the organisation might prefer wireless connectivity.

May not have space for cables to be installed

Employees and visitors can move around the building without disconnecting

Adding new users just means giving out the SSID and password

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Describe overtype and insert modes as used in word processors

  • Overtype mode: deletes the current text at the cursor position and replaces the existing characters with new text
  • Insert Mode: pushes the existing text away as new text is inserted between the existing text
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Explain why it is beneficial to get more RAM instead of relying on virtual memory.

  • More RAM will improve the performance of the computer 
  • More RAM will speed up the access to data
  • Excessive use of VM can cause disk thrashing which decreases performance
  • VM is slower to access than RAM direct (because it has to go back to RAM first)
  • Moving data between RAM and VM takes processor time
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Explain how the operating system performs job/process scheduling/management

  • The OS allocates CPU time to each process, and prioritises them in the order of importance
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When developing a network security policy, it is important to understand the threats that can be made against a network. ‘IP spoofing’ and ‘back doors’ are two techniques that can compromise the security of a network. Describe each of these techniques.

IP spoofing

A technique used to gain unauthorised access to a computer whereby an intruder sends messages to that computer from a false IP address

Back door:
An undocumented method of gaining access to a program, online service or an entire computer system

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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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State the name of the storage space used by the operating system when there is insufficient RAM

  • virtual memory
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State the formatting features used in Ms Excel

  • Font Formatting:

    • Font Style: You can change the font style (e.g., Arial, Times New Roman) for cell content.
    • Font Size: Adjust the size of the text within cells.
    • Bold, Italic, and Underline: Apply these formatting options to emphasize text.
    • Font Color: Change the color of the text.
  • Cell Formatting:

    • Number Formats: Apply various number formats, such as currency, percentage, date, and time.
    • Cell Borders: Add or remove borders around cells or cell ranges.
    • Fill Color: Change the background color of cells.
    • Text Alignment: Control how text is aligned within cells (left, right, center, top, bottom).
    • Text Wrapping: Allow text to wrap within a cell if it's too long to fit in one line.
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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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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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Explain why a software developer should be responsible for addressing ergonomic issues in software design.

Responsibilities of the software developer is to ensure that the ergonomics focuses on making software user-friendly, reduces repetitive motions or eyestrain and enables movements of users to promote comfort and efficiency.

Software can be designed with adjustable text sizes and screen brightness settings to prevent eye strain, offering users a way to customise their visual experience for better comfort during prolonged use.

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Identify one component common to all computers.

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

  • it generates and/or allocates an IP address
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Give three characteristics of an IP address.

  • consists of values between 0–255 / 0–FFF
  • values are separated by full stops/colons
  • it is a unique address
  • can be static or dynamic
  • can be public or private
  • can be IPv4 / have four groups of digits
  • can be IPv6 / have eight groups of digits
  • in IPv6: can replace groups of zeros.
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Explain how the techniques of

(i) verification,
(ii) validation
are used to ensure that the stored data is as accurate as possible.

Dual input of data

  • Two inputs are compared by the system and any discrepancies are reported (and not stored.)
  • Data input once, either printed out or checked on the screen and  errors corrected

 Rules are given to the processor

  • Only accept A, B, C, D, E, F, G i.e Any other input rejected.

Drop-down list/radio buttons

  • Provides only valid inputs, so no other validation is required
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State two reasons for the increased use of computers in offices                      (2 marks)

  • They are small and fit in a small storage space
  • They are portable hence can be carried when need to be used outside the office
  • Low power consumption
  • Have rechargeable batteries
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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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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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Compare the use of a compiler with the use of an interpreter to translate code

Both translate source code written in high level programming languages into machine code.
Compiler: Produces a single executable file that is portable between machines
Interpreter: Source code needs a special environment to run
Compiler: Needs to be compiled for a particular architecture
Interpreter: Can run on any architecture that has the translator/interpreter
Complier: Entire source code file is translated at once
Interpreter: Code is translated line by line
Compiler: Provides error report at the end of the compilation
Interpreter: Errors more obvious in the sequence
Compiler: The program source code is not available (so helps protect IP)
Interpreter: Source code is available
Compiler: Only has to be translated once (affecting the speed of execution)
Interpreter: Has to be translated each time, therefore (affecting the speed of execution)
Compiler: Requires two files to be maintained (one for execution and for editing purposes)
Interpreter: Requires only one file to be maintained
 

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