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Q&A-KCSE Computer Studies Paper 1

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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What is block operation as used in Microsoft word?

An editing or formatting procedure that is carried out on a selected block of text in a word-processing document.

A formatting or editing operation that is applied to a block of text after selecting. The block of text can be a paragraph, line, word, page or the whole document. It is much easier to apply editing or formatting to a block of text than to apply it to every single character

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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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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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Give a reason why HMTL is not regarded as a programming language

  •  It does not have declaration part
  • It does not  have control structures
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Name four data management tools used in spreadsheets. (2 marks)
- Filtering - Sorting - Input validation - Subtotals - Data entry forms
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A large comprehensive school has over 500 computers connected to their Local Area Network (LAN) with a connection to the Internet. (a) Describe, in detail, four disadvantages for the school of having a network of computers compared to stand alone computers

 A network manager may need to be employed  which might be expensive

Could be infected with a virus that could spread to all other computers

Security problems receive traffic from other networks

Hackers may gain access as the network only as secure as weakest point of entry to data and steal/destroy

 The server/switch could go down (main cable break) so all workstations on the network are affected

 Can be expensive to set up as Initial cost of servers, communication devices, switches, network software etc. 

 Substantial Initial disruption: drilling holes, fitting trunking, running cables between buildings etc… 

 Can have a slow response time  due to heavy network traffic so users cannot work as effectively

 Detecting network problems can be more difficult on a network i.e difficult to isolate

 Can be slow to log in to a network  As it slow to download software/check password

 Only limited storage space available on network while one has access to all hard disc drive on standalone computer

 Time and effort to set up users o Can just start a standalone and use computer

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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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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 supermarket uses point of sale (POS) terminals at the checkout for scanning barcodes on the products.

(a) State two items of data that are stored on the barcode.

(b) Describe how the computer system checks that the barcode has been read correctly.

(c) State the type of file access that is used to get the price from the central computer.

(d) Explain how the system updates the file when an item has been sold.

(a) State two items of data that are stored on the barcode.

  • check digit
  • product number/item number/code
  • country of origin
  • manufacturers number/code
  • weight
  • price

(b) Describe how the computer system checks that the barcode has been read correctly.

  • check digit calculation is performed on the check digit, remainder = 0 if the barcode has been read correctly
  • weights and modulus 11 and use remainder
  • or subtractions and addition and use answer


(c) State the type of file access that is used to get the price from the central computer.

  • random/direct/online

(d) Explain how the system updates the file when an item has been sold.

  • search file/master file using barcode number/product code and decrease number in stock/increase quantity sold

KCSE 2021  Prediction Computer Studies Paper 1  Q.16 (c)

c) Distinguish between a source program and a compiler as used in computer programming. [2]

Source program is the original program in a high level language as written by the programmer while a compiler is a program translator that converts source program to object code.

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Describe how the database can be recovered from a system failure

  • backups/dumps of files
  • copy of files on CD/tape streamer
  • file generations
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State four threats that compromise data integrity and state ways that can be used to minimise these threats

State four threats that compromise data integrity

  • Human error
  • natural disaster
  • data transmission errors
  • software bugs

How threats to data integrity can be minimised:

  • Backup data preferably on an external storage media
  • control access to data by enforcing security measures
  • design user interfaces that minimise chances of invalid data entry
  • using error detection and correction software when transmitting data over the network
  • using devices that directly capture data from the source such as bar code readers, digtal cameras, and optical character readers

 

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Define the following terms as used in the internet

HTTPS/HTTP: this is a protocol that is used to send data to web pages across the Internet

Uniform Resource Locator (URL):   a text-based version of a web address

Internet Service provider /ISP  - his is the company that provides a user with a connection to the Internet

browser - Software/application that allows users to view web pages / render HTML -

cookie - a text file (stored by a web browser) that contains data about a user’s browsing habits/details/preferences

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Identify the network component that uses the IP address to send data only to its correct destination

Router

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Give two reasons for connecting computers in a network.
Can share files/data Can share applications/software Can collaborate Can share peripherals (printers, speakers) Can share connectivity (Internet connection, hotspot) Can access files from any computer / hot desk Central control/management (security, software updates, backup, remote support, users, remote monitoring) Allows communication (email, social media, video conferencing, online meeting, collaborative games)
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(a) Name two pieces of hardware needed to enable video-conferencing to take place using a standard computer system.

(b) State one piece of specialist software needed to carry out video-conferencing.

(a)

webcam
speakers
microphone
broadband modem

(b)

use of CODEC (converts/compresses analogue data into digital data)
echo cancellation s/ware (allows talking in real time/keeps everything in sync)
compression s/ware for video/audio
s/ware to access broadband/networking

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Maranda MOCK 2024 CRE Paper 2

b) What Simeon and Anna said about the life of Jesus during the dedication. (7mks)

Jesus would save people

He would bring glory to Israel

He would be a light to the gentiles

He would be a universal savoir

He would bring judgment to the Israelites

Many people would oppose his work

He would reveal secret thoughts of people

He would be the source of redemption for Jerusalem

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List three types of errors that are likely to exist in a program                             (3 marks)

Syntax errors-Incorrect use of programming language

Logical errors- The program do not give the expected output

Runtime errors- Premature end of a program

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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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