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Q&A-KCSE Computer Studies Paper 1

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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Differentiate between uploading and downloading a file

Uploading a file  refers to the process of transferring a file from a local computer to a remote webserver while downloading a file refers to the process of transferring or copying a file from a remote webserver to a local machine

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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 one way developers ensure that their software addresses inclusivity issues.

Incorporate language support features in their software, which allows users to select their preferred language. This can be achieved through multi-language user interfaces and providing translation capabilities. By doing so, developers address language barriers and make the software accessible to a broader audience, demonstrating a commitment to cultural inclusivity.

Gender inclusivity – use gender-neutral language in examples

Cultural/Racial inclusivity – use a variety of ethnicities in photos

Ability inclusivity – represent awareness of disability in some examples

Sexual preference inclusivity – use language that is supportive of LGBTQI+ people

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Confidential information about the students is to be stored on the computer system. Explain the measures that can be taken to ensure that such information remains confidential.

- Passwords
- Hierarchy
- Only allow some staff to access student files
- Only some machines able to access
- Physical location of these machines
- Physical lock on machines
- Encrypted data in files
- Firewall if connected to the Internet

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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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Explain what happens in the computer during the booting process

The booting process is the sequence of events that occur when a computer is turned on or restarted. It involves a series of steps that allow the computer's operating system to initialize and become functional. Here's a simplified explanation of what happens during the booting process:

  1. Power-On Self-Test (POST): When the computer is powered on, the first thing it does is perform a Power-On Self-Test. During this step, the computer's hardware components, such as the CPU, memory, and storage devices, are checked for proper functioning. The POST verifies that all essential hardware components are present and operational.

  2. Bootloader: Once the POST is completed, the computer looks for the bootloader. The bootloader is a small program stored in the computer's firmware or on the bootable device (such as the hard drive or a USB drive). It is responsible for loading the operating system.

  3. Loading the Operating System: The bootloader locates the operating system's files and initiates the loading process. It may display a boot menu allowing the user to choose the operating system if multiple options are available. The selected operating system's core files are loaded into the computer's memory.

  4. Kernel Initialization: The operating system's kernel, which is the central component responsible for managing system resources, is initialized. The kernel sets up essential components such as device drivers, memory management, and process management.

  5. System Initialization: After the kernel is initialized, the operating system proceeds with system initialization. During this stage, various system services and processes are started, and hardware devices are initialized and configured. The operating system loads essential system files and prepares the environment for user interaction.

  6. Login/Graphical Interface: Once the system initialization is complete, the user is presented with a login prompt or a graphical user interface (GUI). The user can then log in with their credentials or interact with the GUI to access the computer's functionalities.

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State advantages and disadvantages of the following system implementation strategies

Phased:
Advantages:

  • only a small part of the operation affected if new system fails
  •  no need to pay for two sets of wages

Disadvantages:

  •  time consuming (each part needs testing fully before expanding system)

Pilot:
Advantages:

  • if new system fails, only that part will be affected
  • possible to gradually train staff on pilot before whole system changes over

Disadvantages:

  •  time consuming (waiting to see how pilot works before rolling out to rest of the organisation)

Direct:
Advantages:

  •  less likely to malfunction since fully tested
  • immediate benefits/less time wasted
  •  reduced costs (only one system so no need to duplicate staff)

Disadvantages:

  • disastrous if the new systems does fail

Parallel:
Advantages:

  •  if new system goes down, there is a backup system in place
  • possible to gradually train staff/staff have time to get used to the new system

 

 

 

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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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Why are CD-Rs and CD_ROMs referred to as WORM?

  • Because data is recorded to the disks once but can be accessed many times without changing the content
  • once data is written to the disk, it becomes read-only and cannot be altered or erased.
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What is utility software?

  • System software that analyses, configures, optimises and maintains a computer system
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State THREE reasons why binary is used in developing digital electronic systems                                                                                                                                                   (3marks)

  • Simple technology is needed to develop both hardware and software.
  • Digital devices are more reliable, small in size and use less power as compared to analog devices.
  • Devices that read, process or output data in digital form are used in computers and other digital devices such as calculators.
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State the differences between a hub and a switch

 

  • switches can send and receive data simultaneously - they are full duplex
  • a hub is half duplex- only one host can communicate at a time.
  • a hub broadcast signals to all computers connected in a network while a switch directs data to its intended destination
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State and explain characteristics of an algorithm

Input : An algorithm can take 0 or more inputs well defined outputs

Finiteness: an algorithm must terminate in finite time and after finite number of steps. 

Definiteness : an algorithm must be clear and unambiguous. Each and every step of an algorithm must be clear and precise and it must have only one meaning

Feasibility: should be feasible with the available resources

 

Output : must produce at least one well defined output

Independent : should have a step-by-step directions which is independent of any programming language

Correctness: should solve the problem it is designed to solve

Efficiency: must take the shortest time possible to run and should require the least memory space. It should use a minimum number of computation steps and memory to produce the desired  output. takes little time and memory to run

Generality: should not be limited to a specific case. It should work for all the valid inputs. works for many possible inputs

Effectiveness : should statements that are relevant to the problem. Every step must be basic and essential. 

 

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Distinguish between real-time and distributed operating systems (KCSE 2018)

  • Real-time OS reads information from input devices and must respond within a short duration of time to ensure correct performance
  • Distributed OS distributes computation among several physical processors which do not share memory or clock
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 Describe four features of the operating system when providing a graphical user interface on a personal computer. Give a suitable example of each feature.

Windows for example a word processing application and a spreadsheet
 
Menus, for example, allow the user to perform operations or run applications such as right-click to create a new folder  
 
Icons for example a picture of linked computers for networking
 
Pointers(mouse or touchscreen)  for example to select items/trigger events  
 
Shortcuts for example to frequently used applications for example having a shortcut to your mail client on your desktop
 
File navigation for example when searching the hard disc for a file/folder using a browser
 
copying / deleting / moving/sorting/naming/searching of files or folders for example copying of a file from the hard drive to a USB pen drive (File handling)
 
Desktop customisation for example changing the colours and background image
 
Copy and paste for example between applications e.g. copying a graph from a spreadsheet to a word processor
 
Error messages for example provide users with error/warning/help messages for example ‘printer out of paper’ 

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Give two different scenarios when a fast broadband connection is essential.

– when transferring large files/attachments with emails
– when streaming music/video files/bit streaming
– when using VoIP/video conferencing
– software updates
– online transactions
– Using VLE (Virtual Learning Environment)

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What is a source code as used in computer programming?

  • It is a program written in a high level langauage
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Outline one advantage and one disadvantage of interviews and questionnaires as data gathering techniques.
 

Interviews

Advantages

  • can gather specific information and additional information
  • high response rate to questions
  • The question can be rephrased to seek more clarification
  • it is possible to win the confidence of the interviewee and get honest answers

Disadvantages

  • time consuming
  • responses to interview questions are subjective.
  • the interviewee may not open up on some sensitive issues
  •  

Questionnaire

Advantages

  • easy to administer
  • can be anonymous.

Disadvantages

  • fixed (inflexible) design
  • potential differences in understanding and interpretation.
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State the factors that affect the performance of the CPU

Number of cores
The number of cores a processor has directly affects the performance of the processor. Each core can perform its own fetch-execute cycle independently of others, so different applications can be allocated to different cores. Quad-core (four-core) and even octa-core (eight-core) processors are becoming common

Cache memory
A processor’s cache is a small portion of incredibly fast memory. It has read and write speeds far higher than hard disk drives and even SSDs. The cache is used to store frequently used information and reduces time wasted in fetching the same information from main memory time and time again

Clock speed
A processor’s clock speed relates to the frequency of the pulses generated by the system clock. The higher the frequency, the more cycles of the fetch-execute cycle can be completed in the same period of time.

Word length
A word is a group of bits that is treated as a single unit by a processor. Words can be used for representing both instructions and data. The length of a word is the number of bits that are assigned to it, with higher word lengths allowing for more bits to be transferred and manipulated as a single unit.

Address bus width
The width of a bus relates to the number wires that make up the bus. Increasing the width of the address bus increases the range of addresses that it can specify, hence increasing the computer’s amount of addressable memory. Adding a single wire doubles the number of addressable memory locations

Data bus width
Increasing the width of the data bus increases the volume of data that can be transferred over the bus at any one time. A wider data bus allows the processor to fetch more data from the main memory in one cycle of the fetch-execute cycle, reducing the number of cycles required to fetch large volumes of data.

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