Modulation refers to the process of converting a digital signal to analog signal at the transmission end while demodulation is to converting analog signal to digital signal at the receiving end

i) To manage the execution of instructions
By running a clock
To decode instructions
(ii) To store OS
To store those parts of applications programs currently running
To store data currently in use
(iii) Part of the processor where data is processed/manipulated
All I/O must pass through here

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

• not able to directly manipulate the hardware
• may need to wait for translation before running
• the program may be less efficient.

 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

• StudentID: String
• FirstName: Required 1
• Year: 2 1
• Email: Email address containing @ sign 1
• AccountBalance: Real

The Fetch – Execute cycle is a sequence of actions, performed by the processor as it fetches
a program instruction from its memory, determines what the instruction wants to do and
carries out those actions. The stages of the cycle are provided below.

• Fetch the instruction – the processor fetches the instruction from a memory address stored in a program counter and transfers the instruction, via a data bus, to an instruction register. At the end of the fetch operation, the counter points to the next instruction that will be read in the next cycle.
• Decode the instruction – the processor decodes the instruction stored in the instruction register, including getting any operands required to complete the instruction.
• Execute the instruction – the decoded instruction is executed.
• Store the result – the result generated by the execute phase is stored in the main memory, and/or sent to an output device. The program counter is updated with feedback from the arithmetic logic unit (ALU), to a different address from which the next instruction will be fetched.

• It ensures that each row has a unique and non-null primary key

• No licence agreement as a certificate of authenticity
• Prices that are extremely cheap
• No documentation manual
• when one connects to the internet for authentication, the report from the manufacturer indicates that the user may be a victim of software counterfeiting
• frequent runtime or occurrence of fatal errors when using the machine

• Users need to ensure that their software is licensed

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

1. Speeds up coding since converting a pseudocode into a programming language is usually faster and easier
2. Acts as documentation
3. Simplifies debugging since logical errors can be identified and corrected early in design stage
4. Language independent since it is not tied to any specific language so can be translated into different languages
5. It uses simple english-like statements

• An end user license agreement (EULA) describes a contract (agreement) between a software developer and a user of that software.
   

• Network operating systems
• Protocols

• Optical scanner is used read data by use a beam of light while a magnetic ink scanner is used to read data encoded/written using magnetic ink by magnetising the ink characters and translating them

• 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 keyboard is an input device used to enter text, characters, and various commands into a computer or other digital devices.

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

• Serial is the transmission of data one bit at a time/through one wire
• Parallel is the transmission of data more than one bit at a time/many wires
• Simplex is the transmission of data in one direction only
• Duplex is the transmission of data in both directions simultaneously

ROM stores BIOS / bootstrap / start-up 

RAM stores currently executing programs and data