1. Enable resource sharing
2. Facilitate remote communication
3. Enable distributed processing
4. Provide better data security and management

• Extra bit on each data-byte that
•  Does not transmit data
• Makes the number of ones in a byte always even or always odd
• Error in the transmission of a bit will make the even/odd wrong
• The problem of two errors in one byte not being found
• Parity block

(a) One from:

• Background checks
• Access control
• Physical security
• User policies

(b) To prevent unauthorised access (1) so that data remains confidential (1) by making it unintelligible (1) because it is scrambled (1)

(a) byte

• fixed number of bits, 8 bits
• represents a character

(b) compiler  program

• converts/changes/translates high-level language into machine code/machine language/low-level language/object code
• changes each high-level language instruction into machine code instructions
• produces an independent program capable of being executed by itself
• all (syntax errors) listed
• converts the whole program before execution/in one go
• converts source code to object code

(c) handshaking

• exchanging of signals to establish communication between two devices/computers e.g. printer and computer, modem and computer

(d) technical documentation

• documentation to ensure that the system can be maintained/updated/altered/developed/upgraded
• trouble shooting/correcting errors/correcting faults
• explanation of what the program does/how the system works
• contains file structures
• algorithms/flow charts/pseudo code
• program listings
• hierarchical chart

(e) simulation

• studying the behavior of a system by using a model/represents real-life/mathematical representation
  e.g. flight simulator (or others), hazardous applications results can be predicted

Word wrap - Is a word processing feature in which a word that does not fit in the current line is automatically moved at the start of the next line

Justification - refers to aligning text on both left and right margins

Drop cap - Make the first character of a paragraph occupy more than one line below it

• 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.

• A compiled program will only execute on a processor of specific type/family/with same instruction set
• A program run using an interpreter can execute on a computer with any type of processor

• System software manages the computer hardware/application software
• application software is for end-user tasks

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 a 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 attack 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

 A network manager may need to be employed  which might be expensive

Could be infected with a virus that could spread to all other computers

Security problems receive traffic from other networks

Hackers may gain access as the network only as secure as weakest point of entry to data and steal/destroy

 The server/switch could go down (main cable break) so all workstations on the network are affected

 Can be expensive to set up as Initial cost of servers, communication devices, switches, network software etc. 

 Substantial Initial disruption: drilling holes, fitting trunking, running cables between buildings etc… 

 Can have a slow response time  due to heavy network traffic so users cannot work as effectively

 Detecting network problems can be more difficult on a network i.e difficult to isolate

 Can be slow to log in to a network  As it slow to download software/check password

 Only limited storage space available on network while one has access to all hard disc drive on standalone computer

 Time and effort to set up users o Can just start a standalone and use computer

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

– multiple choice/yes-no answers
– easy to understand interface e.g. use of icons/drop down menus etc.
– output shown as % probabilities of fault

MAR( memory address register)

• Stores the address/location where data will be read/written/accessed/fetched
• stores address/location of data/instruction being processed
• stores address/location of data/instruction next to be processed

MDR or  memory data register

• Stores the data/instruction that is fetched/read from memory
• stores the data that is to be written to memory
• stores the data/instruction from the address in the MAR
• stores data/instruction next to be processed

 Program counter

• Stores the address/location of the next instruction to be run
• stores the address/location of the current instruction being run

Accumulator

• Stores the result of manipulation/process/calculation

• A non-volatile store of data

• a repeater is a two-port device that amplifies a signal from one port to another
• a switch is a multiport device that uses a table of addresses to send a signal through the correct port

• Phased means that only one part of the system is implemented at a time

 Control unit

DVD - optical media which use one spiral track; red lasers are used to read and write data on the media surface; makes use of dual-layering technology to increase the storage capacity

ROM - non-volatile memory chip; contents of the chip cannot be altered; it is often used to store the start-up routines in a computer (e.g. the BIOS)

SSD/ Solid State Drive/memory (SSD)

non-volatile memory device that uses NAND flash memories (which consist of millions of transistors wired in series on single circuit boards)

Blue Ray -  optical media that uses blue laser technology to read and write data on the media surface; it uses a single 1.1 mm polycarbonate disc

• It prevents double-booking which could happen in paper-based booking system
• The customer gets immediate feedback on the availability of seats
• The customer can make  booking at any time of the day
• Emails provided by customers during booking can be used by companies for advertisement

Multitasking - the  capability of an operating system to enable users to run two or more programs at once on a single computer

Real time processing - data processing system in which the time interval required to process and respond to inputs is so small that the response itself is useful for controlling the physical activity of a process

Time-sharing processing  - a processing mode in which the central processor serves two or more users with different processing requirements (tasks)

On-line processing - is that type of processing where the result of data processing transaction is available immediately