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)

Encryption software

• Scramble/encode/mix up data so it cannot be read/understood if intercepted/stolen

Defragmentation s/w

• Move free space together and Move files together hence enabling Faster access to files

(Data) compression s/w

• Reduce the file size of files or makes files smaller inorder  To use less storage space
• enables Faster transmission
• enables storage of more files

Anti-virus / anti-malware s/w

• To help protect computer/data against viruses/malware
• To scan the computer to look for/quarantine/remove viruses/malware

Disk analysis and repair s/w

• Scan disk and look for faults
• Prevent the loss of data due to faulty disk

Auto-update

•  Checks Internet for new versions of software/OS
• Downloads and installs without user interaction

Firewall

• Examine incoming and outgoing traffic
• To help restrict/prevent unauthorised access over a network

 ...over a network/external source

1. Overheating: Smoke and dust particles can accumulate inside the computer's casing, blocking airflow and hindering the cooling mechanisms of the computer. This can lead to overheating of the internal components, such as the CPU and graphics card. Overheating can cause system instability, performance degradation, and even permanent damage to the hardware.

2. Component Malfunction: Smoke and dust particles can settle on electronic components, such as the motherboard, memory modules, and connectors. Over time, this accumulation can create a layer of debris, leading to poor electrical contact and interference with signal transmission. This can result in component malfunctions, intermittent failures, or even complete hardware failure.

3. Short Circuits: If smoke or dust particles contain conductive materials, such as metal flakes or moisture, they can create a risk of short circuits. When conductive particles come into contact with exposed circuits or connectors, they can cause a direct electrical connection between two points that are not intended to be connected. Short circuits can damage components, disrupt data transmission, and even pose a fire hazard.

4. Increased Maintenance Requirements: Smoke and dust particles can increase the frequency and complexity of computer maintenance. Accumulated dust can clog cooling fans, causing them to work less effectively or even fail. Additionally, smoke particles can leave behind sticky residues that further attract dust, making the cleaning process more challenging.

5. Reduced Performance and Reliability: As smoke and dust particles accumulate within the computer, they can restrict the movement of mechanical components, such as fans or disk drives, affecting their performance and reliability. Dust particles can also hinder the reading and writing capabilities of optical drives or cause errors in data transmission.

• It is a utility software that places file data in adjacent sectors to free up space for more data and reduce access time for files stored

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

• loss of jobs as some traditional shops/banks close
• lower profits for companies that do not get involved with e-commerce
• decline of leisure shopping as goods are bought on-line
• city centres becoming deserted as shops/banks close down
• gap between rich and poor widening as richer get savings from
• shopping on-line
• more people choosing to interact with computers rather than people
• increase in small businesses
• less pollution/travelling

i) To manage the execution of instructions
By running a clock
To decode instructions
(ii) To store OS
To store those parts of applications programs currently running
To store data currently in use
(iii) Part of the processor where data is processed/manipulated
All I/O must pass through here

Legend

• Legends are a small visual representation of the chart's data series to understand each without confusion.

A data series

• is a row or column of numbers that are entered in a worksheet and plotted in your chart, such as a list of quarterly business profits
• A group of related data points or markers that are plotted in charts and graphs

Data Marker

• A symbol on the chart that represents a single value in the worksheet.
• A column, dot, pie slice, or another symbol in the chart that represents a data value

• 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.

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

– 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)

1. Use a humidifier: Using a humidifier can help maintain a consistent level of humidity in the computer lab, which can prevent the negative effects of low humidity.

2. Avoid dry air: Avoid creating a dry environment in the computer lab by opening windows or using fans to increase air circulation.

3. Regular maintenance: Ensure that all computer components are properly maintained and cleaned to prevent damage due to static electricity.

4. Backup data: Regularly backup all important data to avoid data loss in case of hardware failure caused by low humidity.

5. Monitor humidity levels: Use a hygrometer to monitor the humidity levels in the computer lab and take corrective measures if the levels fall below a safe range.

6. Use anti-static materials: Use anti-static mats or wristbands when handling computer components to prevent static electricity buildup.

• user changes his mind
• new government legalisation/company policy company changes
• changes in hardware
• changes in software/upgrades/new versions
• improved operating efficiency/ease of use

• Network
• Commercial
• Enterprise
• Proprietary

Prefixing an extra sign bit- A negative number is representes by prefixing a digit 1 to the number

Ones complement- This is flipping the binary equivalent of the number

Twos complement- this involves getting the ones complement and then adding a 1

• 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.

• a repeater is a two-port device that amplifies a signal from one port to another
• a switch is a multiport device that uses a table of addresses to send a signal through the correct port

download speed :
– speed at which information/data is transferred FROM server/Internet
– speed at which information/data is transferred TO the user’s computer
upload speed :
– speed at which information/data is transferred FROM user’s computer
– speed at which information/data is transferred TO the Internet/server