• Real time  E.g. turning the wheel must turn the car immediately
• On line - Otherwise system cannot be real time

(a) Disk mirroring- Data is written on two or more disks simultaneously.

(b) Encryption - Contents are scrambled so they cannot be understood without a decryption key

(c) Backup - A copy of the data is taken and stored in another location

• More RAM will improve the performance of the computer 
• More RAM will speed up the access to data
• Excessive use of VM can cause disk thrashing which decreases performance
• VM is slower to access than RAM direct (because it has to go back to RAM first)
• Moving data between RAM and VM takes processor time

Syntax error

• An error in the source code of a program like pront("Hello, " + name) instead of print
• These are errors that emanate from improper use of language rules such as spelling mistakes,improper use of variables and misuse of reserved words

Logical error

• A mistake in a program's source code that results in incorrect or unexpected behaviour like if age == 65: print("Eligible for a discount.") instead of using if age >= 65: print("Eligible for a discount.")
• These are errors that occur due to imperfect comparisons

Run-time error

• An error which occurs when a program is asked to do something that it cannot, resulting in a ' crash'9. For example, asking a number to be divided by 0 such as 72/0.
• An error that results in a sudden halt of an executing program

RFID stands for radio frequency identification. There is an RFID reader and tag.RFID is used in contactless credit and debit cards as well as in some hotel room cards. Inside an RFID tag is a chip that contains a small amount of memory. The chip is attached to a coil of wire which acts as an antenna. When an RFID tag is scanned, the reader emits radio waves which are picked up by the tag’s antenna. The power induced in the tag’s antenna from these waves is enough to power the chip which then uses its antenna to emit its own radio wave, which contains the information held on the chip. This wave is picked up by the reader which decodes the information and returns the information to a computer.

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

• Data Integrity: they provide ways or mechanisms for enforcing data integrity constraints, such as referential integrity. If a record in the parent table is deleted, related records in the child table also get deleted. This ensures accurthe acy and consistency of data stored in the database
• Data Security
• Concurrency control
• Reduces data redundancy
• Data retrieval and querying
• Data indexing
• Data consistency and acid transaction
• Data backup and recovery
• Data sharing and collaboration
• Convenient data maintenance

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;

• To get the latest features
• To update security features

• 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

(i) Jobs collected together for processing at a later time
(ii) Output produced quickly enough to affect the next input
(iii) User has direct contact with the processor
(iv) User cannot communicate directly with the processor

• It is a program written in a high level langauage

• Broadcast Radio
• Infrared
• Bluetooth
• Microwaves
• Satellite

System Stability: Computers require a consistent and stable power supply to function properly. Fluctuations or interruptions in the power source can cause various issues that can disrupt the computer's operation or lead to hardware damage.

a. Data Loss: Sudden power outages or voltage fluctuations can cause the computer to shut down abruptly, resulting in data loss if unsaved work is not properly stored. This can be particularly problematic when working on critical tasks or handling important files.

b. Hardware Damage: Power surges or inconsistent power supply can damage the computer's internal components, including the motherboard, CPU, memory, and storage devices. These damages can result in system instability, reduced performance, or even complete hardware failure.

c. Operating System Corruption: Abrupt power loss or inconsistent power supply can corrupt the operating system files, leading to system crashes, error messages, and instability. This may require system repairs or reinstallation of the operating system.

d. Component Lifespan: Inconsistent power supply can put unnecessary stress on computer components, shortening their lifespan. Frequent power fluctuations or surges can cause wear and tear on various parts, reducing their efficiency and overall longevity.

(a) Like "*kenya*"

• Returns the records of all countries that contain the string "kenya"

(b) Like "*ina"

• Returns records for all countries/regions whose names end in "ina", such as China and Argentina.

(c) Like U*

• Returns records for all countries/regions whose names start with "U", such as UK, USA, and so on.

(d) Not Like U*

• Returns records for all countries/regions whose names start with a character other than "U".

(e) >= "Mexico"

• Returns records of all countries/regions, beginning with Mexico and continuing through the end of the alphabet.

(f) Like "[A-D]*"

• Returns records for countries/regions whose names start with the letters "A" through "D".

(g) "USA" Or "UK"

• Returns records for USA and UK.

https://support.microsoft.com/en-us/office/examples-of-query-criteria-3197228c-8684-4552-ac03-aba746fb29d8

• 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

• 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

• Unsigned integers store more positive values

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

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