1. Identify any computer output device suitable for each of the following tasks:

1. Generating receipts where carbon copies are required  (1mk)

• Impact printers e.g dot matrix

     b) an architectural drawing where precision is required         (1mk)

• Plotter

(c ) producing document output for a visually impaired person (1mk)

• Braille/speakers

1. Pesa Tele has offices in Nairobi and Kampala connected in a network . the management is convinced that someone is illegally gaining access to the data in their computers. State three ways in which the company can overcome this problem (3mks)

• Encryption
• Firewall
• Audit trail/tracking
• Use of passwords
• Limit the number of log-in attempts

1. Explain two ways in which the use of internet could make reporting of corruption easier (4mks)

• Interactive: the internet based technology enables real-time dialogue hence instantaneous reporting of cases
• Outreach: the technology allows the coverage of wide areas
• Social mobilization : it easy to create a network of people with similar concerns
• Anonymity : it is easier to report corruption without being  known
• Security: the message sent reaches destination without being intruded

1. State ways in which software errors can be prevent during program development

• Use of antivirus software
• Performing system update frequently
• Testing the software before implementation
• Proper training

• The user can access the source code  so, they can tailor the software to their needs and they can fix any bugs in it
• the source code could be studied for educational purposes
• The user can redistribute the software/program  but this must be done under the same terms as the original software

17. a) i) Explain the term search as used in the Internet.                                            [2]

A web based application that locates items or information from the World Wide Web

ii) Peter intends to download a movie from the Internet. State the three factors that may determine the total time taken to complete the download.                                           [3]

• Size of the video/format
• The bandwidth of the media/speed of network/network traffic
• Type of browser software
• Background activities running in the computer
• Restrictions enforced in the computer/firewall/antivirus
• Speed of the computer/CPU speed
• Size of RAM

b) Wakulima online is an organization that runs a web based system for assisting farmers to obtain market for their produce. State four technological reasons that may cause a farmer not to access the organization’s system.                                                                                  [4]

• Poor network/lack of connection
• Software failure in the system

• Hardware failure
• Lack of access rights
• System overload/hanging
• Lack of skills/disability/illiteracy
• Lack of power supply

c) Explain a situation when each of the following Desktop Publishing program features may be used when creating a publication:

i. Cropping                                                                                                               [2]

Applies to graphics – used to trim/remove/hide some portions in the graphics

ii. Transparency                                                                                                         [2]

Used to make background of a graphic to be clear/visible

d. List two areas where infrared waves are used in data communication.                             [2]

18. a) List four activities of the planning stage of systems development.                             Ignore this question, marks redistributed elsewhere

b) Explain a circumstance when each of the following feasibility studies are carried out during systems development.

i. Technical                                                                                                               [3]

Done to determine whether technology exists to support the proposed solution

ii. Economic                                                                                                              [3]

Done to determine whether the proposed solution is economically viable

iii. Schedule                                                                                                               [3]

Done to determine whether the proposed system can be done within an acceptable time.

c) Table 1 and Table 2 are related tables in a database. Use them to answer the questions that follow.

Table 1

Table 2

i. Identify the appropriate primary key for each table.                    [2]

Table 1 – Dept code, Student Registration No

ii. Explain two benefits of enforcing referential integrity in the database. [4]

• No record can be added in Table 2 if its corresponding record in Table 1 does not exist
• No record in Table 1 can be deleted without first deleting the corresponding record in Table 2
• Reduces data redundancies/ensures integrity
• Prevents deletion of related table

19. a) Describe each of the following validation checks as used in data processing.

i. Preserve check                                                                                                      [2]

Ignore this question, marks redistributed elsewhere

ii. Data type check                                                                                                    [2]

Ensure correct type of data is entered for the field

iii. Check digit                                                                                                           [2]

This is a number added/calculated by the computer to a binary number. The check digit ensures correct transmission of the binary number.

b. Write each of the following abbreviations in full:

i) BCD                                                                                                                                    [1½]

Binary Coded Decimal

ii) EBCD                                                                                                                                 [

This question was thrown out and marks redistributed elsewhere

iii) ASCII                                                                                                                    [1½]

American Standard Code for Information Interchange

c) Using 10-bits binary number system, perform the following decimal operation using two’s complement.                                                                                                                                   [6]

12910 - 12810

+129 = 00 1000 0001

128 = 00 1000 0000

-128 = 11 0111 1111 (ones complement)

                            +1

          11 1000 0000 (Twos complement)

129- 128

     00 1000 0001

+ 11 1000 0000

 100 0000 0001

Hence = 00 0000 00012 or 12 (the overflow bit is ignored)

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.

Convert the HTML into a webpage which is rendered on the screen

• Use of debugging utilities
• Use of test data
• Dry run / Desk checking

• It can now process two instructions simultaneously (where suitable) increasing the performance.

• Knowledge base – is the systems’ database of knowledge about a particular subject. It contains relevant facts, beliefs, assumptions and procedures for solving a particular problem
• Inference engine – this is the software that controls the search for knowledge in the knowledge base and produces conclusions. It takes the problem posed by the user and seeks to analyze it in order to arrive at a conclusion.
• User interface- this is the display screen that enables the user interact with the system.

Trojan (horse); a program which misleads the user into thinking it is another

piece of software which, when run, executes another program;

Spyware; a program which records data such as usernames and passwords on

a host system and forwards the information to a third party;

Adware; code embedded or attached to program files which will persistently

show adverts (that attempt to generate revenue);

Worm; code which will run autonomously and replicates itself on a host system;

Ransomware; a program that encrypts user’s data to make it unreadable until

they pay for the key;

Remote Access Tool (RAT); allows access to control and monitor a computer

from a remote network location;

Rootkit; malware that has managed to gain ‘root’ admin privileges;

Bots/Zombies; a program installed on a computer that performs a job for the

remote owner of the bot/zombie such as sending spam or sending web requests

to perform a DOS or attacking a computer system;

Scareware; malware that tells you something is wrong with your system in an

attempt to get you to make a purchase;

Keylogger; a program that monitors/records a user’s keystrokes in order to steal

passwords/confidential details;

The data before encryption is known as .......plain.................. text.
To scramble the data, an encryption ......................key.........................., which is a type
of ...................key............................, is used.
The data after encryption is known as ....................cipher............................. text.
Encryption prevents the data from being ......................understood...................... by a hacker

• Network
• Commercial
• Enterprise
• Proprietary

• the pain felt in muscles, nerves and tendons caused by repetitive movement and overuse.
• Injury as a result of repetitive use of parts of the body while performing work
• Strains and injuries due to prolonged typing and use of the mouse

Control Unit; Decodes instruction; Controls the fetching and writing of data;

Arithmetic Logic Unit/ ALU; Executes mathematical instructions;  Executes logical instructions; Compares values held in registers;

 Clock; Controls the number of instructions carried out each second;   allows the CPU to synchronize operations;

• connects different networks
• transfer data packets from source to destination
• allow hosts on different networks to communicate

Uses transistors( resistors and capacitors) . It can be implemented by the use of NAND or NOR gates. Data is stored on the chip as a charge

• Easy to add nodes
• Managed centrally
• Fewer data collisions
• A single node failure does not affect the rest of the network

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

• data must be accurate/up-to-date
• personal data must be registered
• data must be used for the purpose that is registered for
• if data is to be used for another purpose the registrar must be notified/
• subject gives consent
• patients must be able to see the data and have it changed if it is incorrect
• processed fairly and lawfully
• kept no longer than needed
• kept secure
• not transferred to other countries without protection

• Real-time processing is where data is processed as it is received and the output is made available immediately to influence the ongoing activity
• Interactive processing is computer processing in which the user can modify the operations appropriately while observing results at critical steps

The user is not allowed to access the source code so, they cannot tailor the software to their needs and  they cannot fix any bugs in it

The software is still covered by copyright

The user must get the owner’s permission to do anything beyond using it