• Object code refers to a program in machine language while source code to a program in a high level language that must be translated to object code for it to be machine readable

Serial

• -more accurate/fewer errors over a longer distance
• -less expensive wiring  
• less chance of data being skewed/out of synchronization/order

Without a primary key, a table in a database may have duplicate rows, making data not uniquely identifiable. This can lead to issues with data integrity and challenges in maintaining relationships between tables. Retrieving and updating specific records becomes problematic, and setting referential integrity constraints is impossible, potentially leading to loss of data.

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)  i)  Explain what is meant by the term volatile memory                                                            (1mark)

• Memory content is lost when the power is turned off

ii) What is normally stored in the non-volatile part of a computer’s main memory                       (1mark)

• The Computer’s BIOS

b) Explain why having cache memory can improve the performance of the CPU                         (2mks)

• Frequently used data/instructions are store in the cache; Meaning they don’t have to be fetched from the main memory;
• Data/instructions stored in the cache memory can be accessed faster (than data/instructions stored in the main memory) MAX 2

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)

•  It does not have declaration part
• It does not  have control structures

Describe how the computer on board the aeroplane uses GPS to find its exact location

– satellites transmit signals to onboard computers
– computers receive/interpret these signals
– system depends on very accurate timing/use of atomic clocks
– each satellite transmits data indicating location and time
– computer in aeroplane calculates location based on at least three satellites
– at least 24 satellites in operation at any one time
– position accurate to within one metre
– can also calculate altitude of aeroplane
– ref to “triangulation”:

Give two benefits of using GPS in this application

– safer as the known location is exact/more accurate
– reduces the possibility of pilot error
– allows accurate estimation of arrival time
– display and guide the pilot to the nearest airport in case of emergency

A computer system refers to computer components that collectively function as a single unit to achieve the desired goal. It can also be defined as a collection of hardware, software, and liveware that work together to receive, process, and manage data

Blagging

• This is where a victim is tricked/persuaded by a fraudster to give their details or payment information for a false reason/purpose;

Phishing

• This is where the victim receives and responds to communication that appears to be from a valid or known source but is in fact fraudulent. (It allows the fraudster to capture private information before the victim realises);

Shouldering

• This is where someone watches and records\remembers a victim entering their pin or security information such as passwords. (They can then use this information to gain access to a system)

(The parent can) set criteria for the websites she is allowed to visit such as a whitelist/blacklist of websites. The firewall will examine the data/traffic incoming and outgoing from her computer. If data is sent from a website that is not allowed, it will be blocked

Multimedia Capability - A laptop with strong multimedia capabilities is essential for a computer studies project submitted on CD-RW. This ensures that the laptop can efficiently handle multimedia content, providing a seamless experience in creating and presenting project materials.

Processor Speed - Opting for a laptop with a high processor speed is crucial. This feature enables the smooth execution of multiple applications simultaneously, enhancing overall project efficiency and reducing processing delays.

Hard Disk Capacity - Consider a laptop with ample hard disk capacity, as the Microsoft Office suite used in computer projects requires significant space for the installation and storage of project files. A spacious hard drive ensures that there is sufficient room for data and applications.

Main Memory Capacity - Given that students often work with multiple programs concurrently during a project, it's important to choose a laptop with an adequate main memory size. A smaller main memory may result in performance issues, hindering the seamless operation of various software applications during project development.

• RAID 10 is a combination of RAID 0 (zero) and RAID 1 (one)

Shielded twisted pair cable:
A twisted pair cable is made up of four pairs of twisted copper wires, a shielded twisted pair cable applies a shield to each one of the pairs on a cable or to all of the pairs together. This shield can reduce EMI (electromagnetic interference), which would be emitted from heavy machinery. This increased data transmission quality in the workshop. STP can also reduce crosstalk.

• Binary can represent two states because computer circuits use transistors, which can either be on or off

• Financial accounting
• Prediction and forecasting
• Inventory keeping
• Budgeting
• Keeping records