Computer Organisation & Architecture

Question 1

Arithmetic Logic Unit (ALU)

Answer 1

performs arithmetic calculations and logical operations

Question 2

Control unit

Answer 2

controls and coordinates activities of CPU/directs operations of all other components in processor

Question 3

System clock

Answer 3

generates regular clock pulses by emitting a series of signals that oscillate between 0 and 1

Question 4

General purpose registers

Answer 4

special memory cells that can be accessed quickly - temporarily stores data and controls information

Question 5

Registers

Answer 5

locations of computer memory within the processor that provide extremely fast access

Question 6

Program Counter (PC)

Answer 6

holds the address of the next instruction to be executed by processor

Question 7

Current Instruction Register (CIR)

Answer 7

holds current instruction that processor is executing

Question 8

Status Register (SR)

Answer 8

records the condition of the CPU as a result of arithmetic, logical or command operations

Question 9

Memory Address Register (MAR)

Answer 9

temporarily holds address of memory location in main memory from which data or instruction is either read from or written to

Question 10

Memory Buffer Register (MBR)

Answer 10

temporarily stores the data read from or written to memory

Question 10

Accumulator

Answer 10

stores results of any calculation processed by ALU

Question 11

Instruction set

Answer 11

set of all operations that can be executed by a processor

Question 12

Opcode

Answer 12

part of an instruction that tells the CPU what operation to perform

Question 13

Operand

Answer 13

element that identifies the values to be used in a calculation e.g. data value, memory address or register

Question 14

Direct addressing

Answer 14

where operand holds memory address of the value to be operated on

Question 15

Immediate addressing

Answer 15

where operand is the actual value to be operated on

Question 16

Processor

Answer 16

part of the computer that processes data by executing program instructions

Question 17

Main memory

Answer 17

memory that can be directly accessed by the processor - consists of memory locations that store instruction/data as binary sequence

Question 18

Bus

Answer 18

set of parallel wires connecting two or more components of a computer

Question 19

Control bus

Answer 19

sends control signals that manage operations that take place inside the computer system - also carries the clock signal

Question 20

Data bus

Answer 20

used to transfer data/instructions to and from the processor

Question 21

Address bus

Answer 21

used to identify the physical address of a memory location to either read/write data from/to that location

Question 22

Word

Answer 22

amount of data that can be handled at one time by the processor

Question 23

I/O Controller

Answer 23

device which interfaces between I/O devices and processor - provides a set of addressable registers that processor can access to communicate with the I/O devices

Question 24

Von Neumann Architecture

Answer 24

where memory is used to store both programs and data together

Question 25

Harvard Architecture

Answer 25

uses separate memory for data and programs/instructions

Question 26

I/O interrupts

Answer 26

occurs when computer is performing a data transfer operation to an I/O device has an error during transmission

Question 27

Timer interrupts

Answer 27

occurs when an allotted amount of time has expired and an action needs to be performed

Question 28

Hardware interrupts

Answer 28

hardware failure has occurred and needs to be addressed

Question 29

Cache memory

Answer 29

small volume of high-performance RAM built directly into processor - acts as a temporary storage area that the processor can retrieve data from easily