device: beeper/loud speaker
use: to indicate barcode correctly read/error in reading barcode
device: (LCD) screen/monitor
use: to show prices and other information about goods
device: touch screen
use: to show prices and other information about goods/to select items that need to be
weighed/identified
device: weighing machine
use: to find weight of loose items (e.g. fruit) to enable pricing
device: (magnetic) card reader/CHIP and PIN reader
use: to read customer’s debit/credit card/enable customer to pay for goods using a
credit or debit card
device: printer
use: to print receipts

• A laser printer makes use of powdered ink and static electricity to print
• Unlike inkjet printers which print line-by-line, laser printers print the whole page in one go

Steps

• The data from the  file to be printed is sent to a printer driver
• The printer driver checks that the data is in an understandable format
• The printer driver checks if the printer is able to carry out the print job
• The data is sent to the printer and is stored in a printer buffer
• A printing drum in the printer is given a positve charge. A laser beam removes the positive charge in some areas. This leaves negatively charged areas which matches the characters/images to be printed
•  

• The preparation of a system proposal which lists the problem definition, objectives of the study, terms of reference of study, constraints, and expected benefits of the new system, in light of the user requirements

• Websites – any inappropriate websites ie pornography, drugs, guns,
• terrorism etc. e.g. is it acceptable for the organisation to allow access to this
• sort of material when you can’t control who is accessing the service?
• Time – limit amount of time, they may not want to provide indefinite access
• or may want to charge for access after the time limit has expired.
• Preventing file sharing and illegal sharing\use of copyrighted materials.
• Accountability – identification of users and actions on a network by
• preventing anonymous access.
• Prevention of illegal activities such as terrorism and fraud.
• The responsibility to keep children safe and protected.
• Responsibility to keep users (customers) data safe and secure.
• Spoofing of websites, phishing. Responsibility of organisation to put some kind of protection in place, eg filtering of known fraudulent sites.
• Recording of private messages or details if not encrypted.
• Recording of usernames and passwords that the user may also use to access other systems.
• Responsibility of organisation to secure their systems from possible attack.
• Sales and marketing – providing sales leads to market products.

emails: – fast delivery of messages (to recipient’s mail box)
– able to send attachments
– can store messages for later use
– auto-translation no language problems
– can open email at a convenient time
video conferencing/calling/chat:
– removes need to travel (saves time and money)
– allows face to face discussions
– works in real time (only allow once)
VoIP: – much cheaper than normal international calls
– direct communication between people
– works in real time (only allow once)
chat rooms/instant messaging:
– instantaneous reply
– anyone can join in
social networking:
– can ensure only your “friends” are in communication
– usually free to join and use
– talk to (multiple) friends at the same time

State the characteristics of each of the following network topologies (KCSE COMPUTER STUDIES 2021 )

i) Mesh Topology  (2mks)

• a host/node is connected to one or multiple hosts
• a   host/node in point to point connection with every other host or a few hosts
• hosts/nodes in mesh topology also work as relays for other hosts which do not have point-to-point links

(ii) Ring Topology (2mks)

• each host/node connects exactly to two other hosts
• data travels around the ring in one direction through all intermediate hosts
• failure of any host results in the failure of the whole ring

1. a) Based on Deutro-Isaiah, describe the Messiah. (7mks)

The Messiah would be despised/ rejected

The Messiah would be treated harshly/ arrested/sentenced to death

The Messiah would be reconciling people through His suffering

The death of the Messiah would bring forgiveness of sins of humankind

The Messiah would endure suffering/humiliation without complaining/ would suffer innocently

The Messiah would have nothing attractive

The Messiah would be humble/simple

The Messiah would be highly honored

The Messiah would succeed in His work

He would be despised, rejected, wounded oppressed and afflicted 

He endured pain and suffering which would have been ours. 

Because of our sins he was wounded 

We are healed by the punishment he suffered He was treated harshly but he never said a word 

He was put in the grave with the wicked 

He was buried with the rich even though he did not commit a crime 

He took the place of many sinners and prayed that they might be forgiven.

• Extra bit on each data-byte that
•  Does not transmit data
• Makes the number of ones in a byte always even or always odd
• Error in the transmission of a bit will make the even/odd wrong
• The problem of two errors in one byte not being found
• Parity block

• It refers to a system software that provides a platform for installation and execution of an application software and also manages the computer hardware

• 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..

• A barcode is one-dimensional while a QR code is two dimensional
• Barcodes are a set of vertical lines and QR code contains squares
• QR codes can be read from any angle . Barcode is only above or below and lined up horizontally

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

A backup is a copy of data that can be used if the original data is lost.

• To detect and remove errors
• To confirm if the program produces the expected output

The following are some of the possible definitions:

It is system software designed to help the users to analyse, configure, optimize, or maintain a computer

System software that helps maintain the proper and smooth functioning of a computer system

Examples include antivirus software, Disk clean-up tools, disk defragmenters, backup software, etc

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.

• she had actually described verification
• data could be incorrect, therefore same incorrect data typed in twice
• accept description of validation process e.g. range check

SECTION A (40 MARKS)

1.What is meant by

    a)Analogue data

     b)Digital data                           (4 mks)

2. Distinguish between transcription and transposition types of errors and give an example of each  (4mks)

3. a)What are peripheral devices?  (1mk)

   b)Give two examples of peripheral devices  (1mk)

4a)What meant by the term user-friendly as used in software development? (1mk)

  b)Distinguish between the terms single-tasking and multi-user as used in operating systems  (2mks)

5.What actions should be taken in case of a fire outbreak in the computer laboratory?  (4mks)

6a) What is an Internet Service Provider?    (1mk)

  b) An employee in a business company is charged with the responsibility of putting the company advertisements on the Internet.

 i) State the professional title of the employee. (1mk)

ii) Give an example of software used by this employee to carry out the above task.    (1mk)

7.Differentiate between COM ports and LPT ports     (2mks)

8.Explain two ways in which ICT can enhance commerce.  (2mks)

9. Explain the following software terms:

    a) Portability       (1 mk)

    b) Modularity      (1 mk)

10. a) State two application areas of desktop publishing software. (2mks)

     b) Explain the following graphic terms:                                                                                     

     i) Rotate (1 mk)

    ii) Crop  (1mk)

12. a)List two arithmetic operations that can be performed on a row of numeric data in a word processing table.    (1 mk)

     b) In each case of (a) above, write the expression used.  (2mks)

13. List two methods of gathering information during the system development process   (2mks)

14.Name three types of optical disks.(3mks)

15.The diagram below shows a formatted plate surface of a storage disk.

            Shade and label:

            a)         one sector                                                                                ( 1mk)

            b)         One block                                                                                (1mk)

SECTION B (60 MKS)

Answer question 16 and any other three questions from this section in the  space provided

16 a) List two examples of:

       i) Third generation languages    (2mks)

       ii) Object oriented languages    (2 mks)

b) Draw a flowchart to compare three non-equal numeric values A, B, C and prints the largest of the three. (11 mks)

17 a) One of the functions of an operating system is job scheduling.  Explain what is meant by job scheduling.   (1mk)

    b)List and explain three types of user interfaces.                      (6 mks)

    c)Describe the following categories of software:

       i) Firmware                 (1mk)

       ii) Proprietary software  (1mk)

     d) a new company XYZ intends to go into the business of desktop publishing. Advise the company on three computer hardware system specification features to consider as a measure of enhancing performance. (6 mks)

18. a) distinguish between the following sets of terms as used in spreadsheets.        (2mks)

     i)Worksheet and workbook

     ii) Filtering and sorting

     b) State one way in which a user may reverse the last action taken in a spreadsheet package.        (1 mk)

     c)The following is a sample of a payroll. The worksheet row and column headings are marked  1, 2, 3, .  and A, B, C.  respectively