• more efficient than a human
• more accurate than a human
• can lift larger and heavier equipment than a human
• can replace humans working in a dangerous environment
• reduces running costs, such as wages and overheads
• can produce consistent results/output
• can work 24 hours a day // do not need to take breaks.

Solid state
 

• Access Controls: Authentication of users in order to access files
• Performing regular patches of updates
• creating secure accounts with required privileges
• scrutinizes all incoming and outgoing packets of data through a firewall
• encryption of data, during transmission
• Log files to detect any breach

• 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..

• 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

Virus / trojan / worm / malware

• Piece of software/code/a program that replicates itself  or causes damage e.g. editing/deleting files

Prevention

• Running anti-virus/anti-malware software 
• don’t download from unknown sources
• don’t click on unknown links

Spyware / malware / keylogger

• Piece of software/code/a program that records actions/key presses and sends this data to a third party analysis

Prevention

•  Running anti-spyware/anti-malware software/firewall

Data interception / passive

• Data is sent to another device and is intercepted by a third party

Prevention

• Encryption

Phishing

• An e-mail has a link that when clicked directs the user to a fake website that collects personal data

Prevention

• Network policy // firewall

Pharming

• A piece of code installed that redirects user to fake website that collects personal data

Prevention

• Anti-malware or firewall

Hacker

• Person attempting to gain unauthorised access to the network/computers/ data/files 
• unauthorised access and then deleting/editing data/files

Prevention

• Firewall
• strong password 
• biometrics
• penetration testing

• Any new or changed files since the last backup

Twisted pair cables

Coaxial cables

Fibre optic cables

A computer keyboard is an input device used to enter text, characters, and various commands into a computer or other digital devices.

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.

Branch of computer science based on enabling computers to
behave like humans/mimic aspects of human intelligence
• AI is implemented in software.
• Combines psychology, biology, linguistics, mathematics, neuroscience,
and philosophy (ethics)
• AI is not the same as the general intelligence of human beings

Uses – Any of the following:
• Game playing (chess, quiz, video games)
• Analytics (analyse buying patterns, predicting behaviours, predictive
text, financial markets)
• Image processing (recognising objects/patterns)
• Logistics (scheduling, order fulfilment)
• Control systems (cars, manufacturing, weapons, navigation)
• Expert systems (medical, mechanical, electrical diagnosis)
• Neural networks (simulating neuron behaviours as in brains)
• Natural languages processing (chatterbots, chatbots, speech
recognition)
• Robotics (dangerous situations, help aged or disabled)

Ethical issues – Any of the following:
• Take the work of humans, thereby affecting employment rates
• Is a computer to be trusted to make decisions (life-death)?

• If a computer discovers something that humans can’t prove, should it be
accepted as truth?
• Do AI machines have rights?
• Will people be comfortable interacting with machines that are
considered intelligent?

SECTION A (40 MKS)

Answer all the questions in this section.

1. a) What is disk formatting?                                                        (1mk)

b) Indicate whether the following devices are used for input or output  (2mks)

i) Plotter

ii)Light pen

iii)Mouse

iv)Visual display unit

2.a)Explain why the following and give one reason why they are not allowed in a computer laboratory. (2mks)

b) For each of the following give one reason why they are not allowed in a computer laboratory.  (2mks)

i) Smoking

ii)Eating foods

3.Distinguish between Real, integer and Character data types as used in programming (3 mks)

4.The cells k3 to K10 of a worksheet contain remarks on student’s performance such as very good, good, fair and fail depending on the average mark.  Write a formula that can be used to count all students who have the remark “very good”      (3mks)

5.a) State the purpose of registers in a computer system               (1mk)

b)Name two multiprogramming operating systems                   (2 mks)

6.a) A series file comprises of records placed in positions 1 to 10.  State the position of the end of file marker.      (1mk)

  b)State the purpose of each of the following: (2mks)

 i)File server software

ii)Communication software

7.a) Name the control structure depicted by the flowchart below.                   (1 mk)

b)Explain the following terms as used in program implementation.      (2mks)

 i)Parallel running

 ii)Direct change over

8. Consider the linear arrays:

 i) AAA (5:50)

 ii)BBB (-5:10)

 iii)CC (18)

Find the number of elements in each array (3mks)

9.Define the term artificial intelligence  (2 mks)

10.Name two types of relationships that can be applied in database design  (2mks)

11.Explain binary Coded Decimal code of data representation (1 mk)

 a)Indenting

 b)Alignment

 c)Word wrap

12.Outline two ways in which a computer can be used in hotels               (2 Marks)

13.a)Explain Binary Coded Decimal code of data representation (1marks)

 b)Write the number 4110 in BCD notation (1 mk)

14.Arrange the following data units in ascending order of size.

   BYTE, FILE, BIT, NIBBlE     (2mks)

15.State two health issues that may result from prolonged use of computers     (2 mks)

SECTION B (60 MARKS)

16. a) State the stage of program development in which  (4 mk)

i) A flowchart would be drawn

 ii)The programmer would check whether the program does as required

 iii)The user guide would be written

iv)The requirements specifications would be written.

b)State the output of the following flow chart segment                  (1mk)

c) i)Draw a flowchart to compute the combined resistance ® of two resistors R1 and R2 in parallel using the formula;

                      (5mks)

ii)Write a program using Pascal or C languages for the flowchart in C (i) above. (5 ½ mks)

17. a)List three paragraph formatting activities in word processing  (3mks)

 b)Differentiate between bolding and highlighting text (2mks)

c) The following information shows the income and expenditure for “bebayote “ matatu for five days.  The income from Monday to Friday was Kshs. 4,000, 9,000, 10, 000, 15,000 and 12,000 respectively while the expenditure for the same period was Kshs.  2,000, 3,000, 7,000, 5,000 and 6,000 respectively

i)Draw a spreadsheet that would contain the information.  Indicate the rows as 1, 2, 3 …. And the columns as a, B, C    (4mks)

ii)State the expression that would be used to obtain:

 I Monday’s profit  (2mks)

 II Total income (2mks)

III)Highest expenditure (2mks)

18.a) Subtract 0112  from 10012 (1mk)

 b)Using two’s compliment, subtract 7 from 4 and give the answer in decimal notation (4mks)

c) Convert

i) 91B16  to octal    (3mks)

ii) 3768   to hexadecimal   (3mks)

iii) 9.62510 to binary  (4 mks)

19.a) Explain what the following DOS commands will do when executed.

    i)  A: \copy *.* B:    (2 mks)

   ii)   C: \> ERASE*. DOC   (2mks)

  iii)   b: \> Md EXAMS  (2mks)

 b)  i)  With the aid of a diagram, explain hierarchical (tree) network topology   (3mks)

  ii)List two advantages and two disadvantage of hierarchical network topology.  (4 mks)

   Advantages:-

   Disadvantages:

20. a)Name and explain the function of the keyboard keys represented by the following symbols.

  b) Simulation is one of the application areas of computers        

  i) What is meant by the term simulation      (1mk)

  ii)Name two application areas of simulation   (2 mks)

 iii) State three advantages of computer based simulation (3 mks)

 c) Explain three ways in which computers have impacted education (3mks)

• compact disks
• DVDs
• Blue Ray

• data must be up to date
•  data can only be read/used for the purpose for which it was collected
• data must be adequate, relevant and not excessive
• data must be accurate
• data must be destroyed when no longer needed/don’t keep longer than necessary
• data user must register what data stored
• data must be used/collected fairly and lawfully
• data must be held securely
• data must be protected from accidental damage
• only authorised personnel can have access to the data
• fines are imposed for data mis-use
• data should not be passed on to a third party without permission
• a person can view data and have it changed/removed if incorrect

1. Enable resource sharing
2. Facilitate remote communication
3. Enable distributed processing
4. Provide better data security and management

• 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

Microwaves can cover shorter distances. On the contrary, radio waves can travel a long distance. Radio wave is usually propagated through sky mode while microwave uses the line of sight propagation. 

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

• 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

• 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