CPU

Question 1

M.A.R - Name and function?

Answer 1

holds the address of the current instruction that is to be fetched from memory, or the address in memory to which data is to be transferred

Question 2

M.D.R - Name and function?

Answer 2

Memory Data Register - Holds the contents found at the address held in the MAR, or data which is to be transferred to main memory

Question 3

Data Bus - Describe + Function?

Answer 3

It can carry data to main memory from the processor and vice versa. The data bus will transfer data to/from the address that is held on the address bus.

Question 4

Address Bus - Function?

Answer 4

It is concerned with passing an address unidirectionally(one way), from the CPU to RAM.

The sole purpose of an address bus is to identify the address of the location in cache or main memory that is to be read from or written to.

Question 5

Control Bus - Function?

Question 6

C.I.R - Name and function?

Answer 6

Holds the instruction that is currently being decoded and executed

Question 7

P.C - Name and function?

Answer 7

Program Counter - Holds the memory address of the next instruction to be fetched from primary memory

Question 8

ACC - Name and function?

Answer 8

Accumulator - Holds the data being processed and the results of processing from the ALU

Question 9

Cache - Function

Answer 9

Cache is a small amount of memory which is a part of the CPU - closer to the CPU than RAM . It is used to temporarily hold instructions and data that the CPU is likely to reuse.

Question 10

R.A.M - Name and function?

Answer 10

RAM is the main place for storing instructions and data whilst a program is being executed . It is also called main memory. Program data is copied into RAM before the CPU can run the program.

Question 11

A.L.U - Name and function?

Answer 11

Carries out mathematical and logical operations e.g 1+1 or 1==1

Question 12

C.U - Name and function?

Answer 12

The CU, which is also called the controller, controls data moving through the processor, and controls the timing of operations and the instructions sent to the processor and the peripheral devices . The CU directs the system to carry out program instructions.

Question 13

Input devices - Function?

Answer 13

An input device allows data such as text, images, video or sound to be entered into a computer system

Question 14

Output devices - Function?

Answer 14

An output device allows data to be transmitted by the computer in a human-friendly form