• virtual memory

• Main memory is transitory/temporary/volatile, secondary storage is (semi-)permanent
• The processor can only use data/instructions that are in the main memory
• Main memory is directly accessible to the processor, secondary storage is not directly accessible to the processor 

– lightweight
– long battery life
– cool running processor
– touch pad
– internal webcam

• RSI in wrists or fingers from prolonged typing or repeated clicking of mouse button
• headaches/eyestrain/dry eye from staring at a monitor for long periods of time/glare from monitor
• back ache/strain from sitting in the  same position for a long time/using chair with no adjustment

• Any new or changed files since the last backup

• All nodes ‘listen’ for traffic to sense when the network is idle.
• When a node wishes to transmit, it transmits a ‘request to send’ frame’ (RTS)
• The intended receiving device will transmit a ‘clear to send’ (CTS) frame if it is available.
• All other nodes ‘sense’ the network is busy and wait a random amount of time before trying to transmit

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

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 employee
• 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

• OS controls operation of system/hardware
• Applications software allows the system to do something useful

• Network operating systems
• Protocols

(i) Incorrect use of language, e.g. PLINT instead of PRINT
(ii) A mistake in the structure of the solution, e.g. a jump goes to the wrong line
(iii) Inappropriate arithmetic is used, e.g. division by 0 is attempted

One to one  - Each record in the parent table has exactly one related record in the child table, and vice versa.

One to Many -  Each record in the parent table can have multiple related records in the child table, but each record in the child table is related to only one record in the parent table

• Websites – any inappropriate websites ie pornography, drugs, guns,
• terrorism etc. e.g. is it acceptable for the organisation to allow access to this
• sort of material when you can’t control who is accessing the service?
• Time – limit amount of time, they may not want to provide indefinite access
• or may want to charge for access after the time limit has expired.
• Preventing file sharing and illegal sharing\use of copyrighted materials.
• Accountability – identification of users and actions on a network by
• preventing anonymous access.
• Prevention of illegal activities such as terrorism and fraud.
• The responsibility to keep children safe and protected.
• Responsibility to keep users (customers) data safe and secure.
• Spoofing of websites, phishing. Responsibility of organisation to put some kind of protection in place, eg filtering of known fraudulent sites.
• Recording of private messages or details if not encrypted.
• Recording of usernames and passwords that the user may also use to access other systems.
• Responsibility of organisation to secure their systems from possible attack.
• Sales and marketing – providing sales leads to market products.

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

• An instruction is retrieved from the memory
• The instruction is decoded
• The instruction is executed
• the program counter is incremented

• Application software refers to software that is designed to help the computer user to accomplish specific tasks
• Examples of application software include; Internet browsers, word processors, spreadsheets, databases etc
• System software is software that performs tasks needed to operate the hardware and provide services to other software
• Examples Operating Systems, Networking software, utility programs(encryption, backup, disk defragmentation software, ...)

• two's complement has only one value for zero

• Use of debugging utilities
• Use of test data
• Dry run / Desk checking

• They run only one program/task
• OS would increase development and manufacturing cost as more storage will be needed

May not have space for cables to be installed

Employees and visitors can move around the building without disconnecting

Adding new users just means giving out the SSID and password