admin@kcseforecast.com

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.

Question Image

State email protocols

  • Simple Mail Transfer Protocol (SMTP)
  • Post Office Protocol (POP)
  • Internet Message Access Protocol(IMAP)
Question Image

List four input devices used to capture data by way of scanning                 

Optical Mark Recognition; Optical Character Recognition; Magnetic Ink Character Recognition ; Optical Bar Recognition

Giving answers as readers is also acceptable, that is, Optical Character Readers, Magnetic Ink Character Readers; Optical Mark Readers

 

Describe two health risks associated with the increased use of computers.

  • RSI in wrists or fingers from prolonged typing or repeated clicking of mouse button
  • headaches/eyestrain/dry eye from staring at a monitor for long periods of time/glare from monitor
  • back ache/strain from sitting in the  same position for a long time/using chair with no adjustment
Question Image

Satellite services are used to provide broadband internet connectivity to regional and remote areas of Kenya. State one advantage and one disadvantage of using satellites for this purpose.

Advantages

  • can cover large areas
  • requires minimal land-based transmission support
  • requires minimal infrastructure to provide internet access
  • minimal impact on the environment or humans.

Disadvantages

  • transmission speeds are not comparable with other forms of transmission
  • data costs are expensive by comparison to other forms of transmission
  • expensive to deliver.
Question Image

Internet and E-mail Questions

Define the term internet      1mk

  • The global interconnection of computer networks for purpose of communication and resource sharing

Explain the term web page    1mk

  • A hypertext  page prepared to display the content on the web

Explain the following internet address http://www.google.co.us in reference to the structure of a URL    3mks

  • HTTP- hypertext transfer protocol or simply protocol
  • WWW – subdomain
  • google – the name of the computer with the web content/domain name
  • .co – top level domain for commercial organization
  • .us- a TLD extension for the country US

 

What is the world wide web                                       1mk

  •  A virtual space on the internet that allows web pages and sites to be accessed

Define the term browser                                    1mk

  •  A software that used viewing of web content

Explain the meaning of the word hyperlink     1mk

  • A text or picture that is a link to another webpage on the internet

What is a search engine?     1mk

  • Is a special program that collects and stores links to information websites allowing users to search its database for them
  • A specialized web-based application that help the user to search for specific information on the internet.

Explain the meaning of the term internet service provider            1mk

  • A company that offers internet services to end-users

Identify three elements apart from a computer that is required for one to be connected to the internet    3mk

  • Modem
  • Internet software
  • Internet service provider
  • Telecommunication lines
  • TCP/IP protocols

 

Define the term modem 1mk

  • Stands for modulator-demodulator
  • A device that enables telecommunication to use telephone lines

What is a protocol? Write the following in full: TCP/IP, HTML, HTTP and FTP           5mks

  • Protocols – are special communication rules that govern sending and receiving of messages by computers on a network
  • Html – hypertext markup language
  • Hypertext transfer protocol
  • Transmission Control Protocol
  • Internet Protocol
  • File Transfer Protocol

What would you do if a website refused to load on the browser within the first attempt?   1mk

  • Click the refresh button on the toolbar

 State three internet services                         3mks

  • Instant messaging
  • E-mails
  • E-commerce
  • Social media and networks
  • E-learning

 

Define the term internet telephony      1mk

  • Transmission of voice data over the internet

State three benefits of the internet in our society

  • Provides a platform for conducting business and marketing
  • Provides many platforms such as social media through which people can contact each other
  • Cost saving
  • Efficient communication

There are four change-over methods used in the implementation stage of the system development life cycle (SDLC): direct change-over, phased, parallel and pilot.

Direct Change-Over

  • A date is chosen for the shutdown of the old system, then at that time, the old system
    is turned off and the new system is implemented

Phased

  • Parts of the new system are implemented in stages or for a period of time, both the old and the new system are running together until all parts of the system are implemented.
Question Image

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
Question Image


Interfaces enable computer users to interact with the operating system. State three advantages of using a graphical user interface (GUI) for loading programs and files.

  • novice can use the system right away
  • user-friendly/easy to select
  • click on icons/picture to select
  • easier to input/words are replaced with icons
  • no need to know command language to use the system/remember
  • command language
  • selecting item using mouse is faster than entering commands
  • avoids typing errors
  • no need to type
  • no need to remember commands
  • no need know the different commands for the different software
  • multitasking (several programs open at the same time therefore easier
  • /faster to switch
  • easier/faster switching between files, folders etc.
Question Image

b) Give one benefit of each type of data transmission

Serial

  • -more accurate/fewer errors over a longer distance
  • -less expensive wiring  
  • less chance of data being skewed/out of synchronization/order
Question Image

The following are software classified according to the end user licence agreement. Briefly describe each of them:

open source software, freeware, shareware, and proprietary software

Open source : refers to software provided freely with its source code. The user can modify and redistribute the software.

Freeware: these are software that can be downloaded for free and distributed, buta  the source code is hidden and cannot be altered.

Shareware: is software that is available for free within a given trial period, after which it must be bought.

Proprietary: software made for commercial purposes. The source code is hidden, and it can only be used after paying for a licence.

 

State the symptoms of a computer virus

  1. Slow Performance: If your computer suddenly becomes significantly slower than usual, taking longer to boot up, open applications, or respond to commands, it could be a sign of a virus. Viruses can consume system resources, resulting in decreased performance.

  2. Frequent Crashes: If your computer frequently crashes, freezes, or experiences sudden system reboots without any apparent reason, it could be due to a virus. Some viruses can interfere with system stability, leading to unexpected crashes or instability.

  3. Unusual Pop-ups or Ads: If you start noticing an excessive number of pop-ups, advertisements, or banners appearing on your computer screen, especially when you're not browsing the internet, it might be an indication of adware or malware infection.

  4. Unwanted Modifications: Viruses can modify system settings or configurations without your consent. If you observe changes in your default browser homepage, new toolbars appearing, unfamiliar icons on the desktop, or altered settings, it could be a sign of a virus.

  5. Unusual Network Activity: If you notice excessive network traffic, unusual data transfers, or a sudden increase in data usage without any known reason, it could be an indication of a virus or malware actively communicating with external servers.

  6. Missing or Modified Files: Viruses can delete, encrypt, or modify files on your computer. If you find missing files or encounter unexpected changes in file sizes, names, or extensions, it could be a result of a virus infection.

  7. Disabled Security Software: Some viruses attempt to disable or circumvent antivirus or security software to avoid detection. If you notice that your antivirus program or firewall is deactivated, modified, or unable to update, it could be due to a virus compromising your security software.

  8. Unexpected Email or Message Activity: Viruses can use infected computers to send spam emails or messages to contacts in your address book without your knowledge. If your friends or colleagues report receiving suspicious or unexpected emails or messages from you, it could be a sign of a virus.

Question Image

Distinguish between a file and a folder

A file is a collection of related data given a unique name while a folder is named storage location on a storage media that contains related files

Question Image

A family has purchased a computer system with the following specification:

Processor speed 2200 MHz
RAM 512 Megabyte
Hard disk drive 120 Gigabytes
CD ROM
DVD writer
Modem 56k
Monitor 17"

(a) The computer has been purchased for buying goods and services over the Internet. Explain how each of these items of hardware would be used for this purpose.

Hard disk drive

RAM

DVD writer
Modem

Hard disk drive

  • to hold the operating system/communication and applications software/ISP software
  • for storing files/information/cookies on backing store

RAM

  • for data, computer programs and operating instructions which are moved into it/downloaded for data currently in use

DVD writer

  • Films/videos/pictures/music/multimedia data downloaded/purchased

Modem

  • link/dial up/establish communication with the Internet
  • Convert digital signals to analogue/audio tones (and vice versa) Which can travel across the telephone system
Question Image

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
Question Image

State what is meant by each of the following modes of data  processing

(i) Batch processing.
(ii) Real-time processing.
(iii) Online processing.
(iv) Off-line processing.

(i) Jobs collected together for processing at a later time
(ii) Output produced quickly enough to affect the next input
(iii) User has direct contact with the processor
(iv) User cannot communicate directly with the processor

Question Image

Distinguish between an optical scanner and a magnetic ink scanner

  • Optical scanner is used read data by use a beam of light while a magnetic ink scanner is used to read data encoded/written using magnetic ink by magnetising the ink characters and translating them
Question Image

Journalists are issued with laptops when they start working at a magazine publishing company. The company only uses free open-source software (FOSS).

  • 2.1.1 Explain the concept of open source in the context of FOSS. (2)
  • 2.1.2 Give ONE example of a free operating system the company could install on a laptop. (1)
  • 2.1.3 State TWO disadvantages of using free open-source software.

The laptops are equipped with either an HDD or an SSD.

  • 2.2.1 Users of laptops equipped with HDDs are advised to defragment the HDD regularly.
  • Briefly explain what defragmentation is. (2)
  • 2.2.2 Write out the abbreviation SSD in full. (1)
  • 2.2.3 Explain why an SSD accesses the data faster than an HDD.

The journalists can access their data remotely using virtualisation or Software
as a Service (SaaS).
2.3.1 Define the term virtualisation. (1)
2.3.2 Office365 is an example of SaaS.
(a) Except for remote data access, state TWO benefits of using
SaaS. (2)
(b) Describe how the license model of SaaS works. (2)

  • 2.4 The company takes precautionary measures to protect the magazine's data.
  • 2.4.1 An incremental backup strategy has been implemented to safeguard data. Explain how an incremental backup strategy works. (2)
  • 2.4.2 The company considers installing biometric readers on all the laptops. How would a biometric reader help safeguard the data on a laptop?

 

2.1.1 Explain the concept of open source in the context of FOSS. (2)

  • Is a software whose source available and user can modify and redistribute

Give ONE example of a free operating system the company could install on a laptop. (1)

  • Linux
  • FreeBSD
  • ReactOS
  • Android
  • ChromeOS
  • OpenSolaris

2.1.3 State TWO disadvantages of using free open-source software.

  • Lack of support
  • Security risks
  • Compatibility issues
  • Hidden costs
Question Image

(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

Question Image

What is a source code as used in computer programming?

  • It is a program written in a high level langauage
Question Image