• It requires that a foreign key must have a matching primary key or it must be null

• 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

State the function of each of the following keys on the computer keyboard :  (2mks)

Backspace;

• Deletes characters to the left of the cursor

Insert

• Add characters at the cursor position
• Toggles between overtype and insert modes

An organization intends to replace an existing system by carrying out the process in stages .

Name the implementation strategy ;  (1mk)

• Phased change-over

Give two reasons why the  organization is opting to use the implementation strategy  in (a) above     (2mks)

• Gives employees time to learn
• Organizations can revert to the old system in case of failure
• Reduces resistance by the employees
• It is easier to find system errors as you are dealing with only one part at a time
• Accessing parts of the old system is still is possible in case of failure of the new system

A manager wishes to replace the current manual system with a computerized one. Describe three areas that must be evaluated to justify the replacement  (6 marks)

• Technical feasibility

• Does the current technology suffice

• Economic feasibility

• Benefits outweigh costs/ whether the project is cost effective

• Schedule feasibility

• Can it be done within the schedule

Headache, back and neck pain may result from the use of computers. State how each of them can be minimized                               (2mks)

• Proper lighting
• Regular breaks
• Use of antiglare
• Correct position of the screen
• Ergonomic furniture

Students of a school intended to elect their school Captain by secret ballot.  State three ways in which computers can be used to improve the election process                          (3mks)

• Registrations of voters
• Voter identification
• Actual voting
• Tallying

Explain why intranet is a more secure way to share files within an organization compared to internet (2mks)

• Intranet involves the interconnection of computers  within  the organization hence it is easier to monitor the access and sharing of files since the users in an organization can be assigned accounts and passwords which will enable to access files they are authorized to access unlike the internet where many can access what is stored in the organization’s website

List two career opportunities directly associated with computer networking               (2mks)

• Network administrators
• Network engineers
• Network technicians

Distinguish between a formula and a function as used in spreadsheets

• A formula is a mathematical expression that returns a value
• A function is an excel inbuilt formula that returns a value given a range of values or arguments

 The C directory of a computer has folders named Form 1, Form 2, Form 3 and Form 4. Each class has students’ folder named according to their admission number.  The student created their own folder for subjects they are studying based on the table below:

• provides an interface between the computer user and the hardware
• Manages the allocation and deallocation of the CPU to processes.
• manages Input-output devices by use of drivers

• Ease of installation and use
• Application software intended for use in the computer
• Processor type. Some processors do not support all operating systems

• It dictates the speed at which data is transferred between these components and enables the sequential execution of instructions in the correct order.
• generates a timing signal that is used to synchronize communication between CPU components and the rest  of the computer system

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 has electrical components.
• It is programmable.

The organisation of files is in a hierarchy/tree structure
A node is either a folder/directory/sub-folder/sub-directory or the file itself
The top node/folder/directory/drive is the root

• Bus topology is characterised by common transmission media shared by all the connected nodes
• Star topology is characterised by a central switching node connected directly to each of the multiple nodes in the network

Advantages of Star topology over Bus topology

• Faster communication as compared to bus topology
• Independent line of connection allows freedom of removing or adding nodes

Disadvantages of Star topology over Bus topology

• Expensive as compared to the bus topology
• Long cable length

Syntax
• An error that occurs when a command does not follow the expected syntax of the language, e.g. when a keyword is incorrectly spelt
• Incorrect: IF A ADN B Then
• Correct: IF A AND B Then

Logical
• An error that causes a program to output an incorrect answer (that does not necessarily crash the program)
• An algorithm that calculates a person’s age from their date of birth, but ends up giving negative numbers

Is an arrangement of people, data, processes, communication and IT that interact to support problem solving

Components of an information system

• Hardware
• Software
• Data - information manipulated by software
• people- all people involved
• Processes - steps to accomplish a goal

Refers to a small piece of software designed to update, fix, or improve a specific part of the operating system or an application.

NB: Patches are typically released by the software's developer or the operating system vendor to address security vulnerabilities, software bugs, or to add new features or enhancements

A PAN exist around a single person whereas a LAN covers a larger area

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)

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

Any four of:
Sequential:
• Individual instructions are executed one after another
• Flow control is accomplished by jump/branch/goto instructions
• Results are usually achieved less quickly than parallel processing (do
not award twice)
Parallel:
• Individual instructions can be routed to different processors for
simultaneous execution
• Results are usually achieved quicker than sequential instruction (do not
award twice)
• Requires multi-core processors or multiple microprocessors
• Tasks may be split into different parts with each part executed on a
different processor
• Results need to be merged back together after completion

Enrolment:
- Data input on line
- Individual records validated
- Speed mismatch implications
- Indexes updated immediately
Exam grades:
- Data input twice
- Off line
- Run as a batch
- At otherwise downtime

• online storage
• incremental backup
• full backup
• RAID (level 0, 1, 10)
• uninterruptible power supply (UPS)

• once instructions are given, the processing runs automatically hence requiring little supervision
• tasks are processed as a group hence reducing the cost
• It is faster since the since runs automatically
• there is increased output since the processor works without any interruption