Answer question 16 and any other three questions from this section in the spaces provided.

16. a) With the aid of a flow chart, describe a loop control structure as used in programming. [4]  

A control structure that allows statement(s) to be repeatedly executed until a certain condition is met                                                                                                      2mks

NB. Accept any other looping construct

• 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

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

A backup is a copy of data that can be used if the original data is lost.

• All the characters and symbols that can be represented by a computer system.
• Each character and symbol is assigned a unique value.

(b) One disadvantage of using the Unicode character set, instead of the ASCII character set, is

that the text stored takes up more storage space

• Each character is encoded using more bits

• do not allow outside floppy disks/CD’s/DVD’s
• use disk free work stations
• download/install and use anti virus software
• scan hard disks regularly
• update the anti virus program regularly
• do not open file attachments from unknown sources/download
• doubtful software from the Internet
• do not use files that come from unknown sources
• buy original software/do not buy pirated software
• use firewalls

• It has electrical components.
• It is programmable.

• Because data is recorded to the disks once but can be accessed many times without changing the content
• once data is written to the disk, it becomes read-only and cannot be altered or erased.

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

• Is the protection of programs and data in computers and communications systems against unauthorized modification, access or disclosure
•  

• This approach causes minimum disruption

• Unfamiliar graphics or quizzical messages appear on the screen
• Programs taking longer than usual to load
• Less memory allowance than usual
• Unusual error messages occurring more frequently

1. Ergonomic Chair: Ensure that each user has an ergonomic chair that provides proper lumbar support. The chair should be adjustable in terms of height and backrest angle.

2. Adjustable Desk: Provide adjustable desks or workstations that can accommodate different user heights and allow for proper positioning of the keyboard, mouse, and monitor.

3. Monitor Placement: Ensure that the computer monitors are positioned at eye level or slightly below to prevent users from straining their necks and shoulders. Consider using monitor stands or adjustable monitor arms for better positioning.

4. Keyboard and Mouse: Encourage the use of ergonomic keyboards and mice that are designed to minimize strain on the wrists and hands. Provide wrist rests if needed.

5. Proper Lighting: Ensure that the computer room is well-lit, with appropriate lighting levels to reduce eye strain. Avoid glare on the computer screens by using adjustable blinds or curtains.

6. Regular Breaks: Encourage users to take regular breaks from prolonged computer use. Suggest the 20-20-20 rule: Every 20 minutes, look away from the screen at an object 20 feet away for at least 20 seconds.

7. Stretching Exercises: Promote stretching exercises for the neck, shoulders, and back to help alleviate muscle tension and improve blood circulation. Display posters or provide resources on desk stretches and exercises.

8. Correct Posture: Educate users about proper sitting posture, emphasizing the importance of maintaining a neutral spine position. Provide visual aids or ergonomic training materials to demonstrate the correct posture.

9. Desk Organization: Encourage users to keep their workstations organized to minimize the need for reaching or straining. This includes keeping frequently used items within easy reach and arranging cables to prevent trip hazards.

10. Individual Assessments: If the backache issue persists, consider offering individual ergonomic assessments for users. A specialist can evaluate the user's workstation setup and suggest personalized recommendations.

• (Cache) Stores regularly accessed instructions/data
• Reduces the need to access instructions/data from the main memory
•  Makes up for the difference in speed of the CPU and main memory

• reduced labour costs/do not need paying
• reduced cost of goods
• improve speed of production/productivity
• high degree of accuracy/precision/less errors
• can operate where humans can not go
• do not take breaks/holidays/get tired
• work 24 hrs a day
• reduce accidents at traffic lights
• improve traffic flow
• can work in dangerous conditions

• To detect and remove errors
• To confirm if the program produces the expected output

(a) Buffer

• temporary storage or memory which compensates for the difference speed of peripherals and the CPU

(b)batch processing

• processing doesn’t start until all data is collected
• JCL (any reference to Job Control Language)
• no need for user interaction
• processed all in one go
• done at “quiet” times
• e.g. billing, payroll, cheque processing

(c) e-commerce

• electronic commerce
• buying and selling products/services using the internet/computer networks

(d) simulation

• studying the behaviour of a system by using a model/mathematical representation
• results can be predicted
• e.g. flight (or other) simulator, modelling hazardous chemical process

(e) Email

• sending messages from one device to another using computer networks/Internet

• 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.

Dual input of data

• Two inputs are compared by the system and any discrepancies are reported (and not stored.)
• Data input once, either printed out or checked on the screen and  errors corrected

 Rules are given to the processor

• Only accept A, B, C, D, E, F, G i.e Any other input rejected.

Drop-down list/radio buttons

• Provides only valid inputs, so no other validation is required