4.1 Central processing unit (CPU) architecture

Question 1

Von Neumann architecture

Answer 1

computer architecture which introduced the concept of the stored program in the 1940s

Question 2

Arithmetic logic unit (ALU)

Answer 2

component in the processor which carries out all arithmetic and logical operations

Question 3

Control unit

Answer 3

ensures synchronisation of data flow and programs thoughout the computer by sending out control signals along the control bus

Question 4

System clock

Answer 4

produces timing signals on the control bus to ensure synchronisation takes place

Question 5

Immediate access store (IAS)

Answer 5

holds all data and programs needed to be accessed by the control unit

Question 6

Accumulator

Answer 6

temporary general purpose register which stores numerical values at any part of a given operation

Question 7

Register

Answer 7

temporary component in the processor which can be general or specific in its use that holds data or instructions as part of the fetch-execute cycle

Question 8

Status register

Answer 8

used when an instruction requires some form of arithmetic or logical processing

Question 9

Flag

Answer 9

indicates the status of a bit in the status register

for example, N = 1 which jndicates the result of an addition gives a negative value

Question 10

Address bus

Answer 10

carries the addresses throughout the computer system

Question 11

Data bus

Answer 11

allows data to be carried from processor to memory (and vice versa) or to and from input/output devices

Question 12

Control bus

Answer 12

carries signals from control unit to all other computer components

Question 13

Unidirectional

Answer 13

used to describe a bus in which bots can travel in one direction only

Question 14

Bidirectional

Answer 14

used to describe a bus in which bots can travel in both directions

Question 15

Word

Answer 15

group of bits used by a computer to represent a single unit

Question 16

Clock cycle

Answer 16

clock speeds are measured in terms of GHz (this is the vibrational frequency of the clock which sends out pulses along the control bus)

Question 17

Overclocking

Answer 17

checking the clock speed of a system clock to a value higher than the factory/recommended setting

Question 18

BIOS

Answer 18

basic input/output system

Question 19

Cache memory

Answer 19

a high speed auxiliary memory which permits high speed data transfer and retrieval

Question 20

Core

Answer 20

a unit made up of ALU, control unit and registers which is part of a CPU
a CPU may contain multiple cores

Question 21

Port

Answer 21

external connection to a computer which allows it to communicate with various peripheral devices
a number of different port technologies exist

Question 22

Universal serial bus (USB)

Answer 22

a type of port connecting devices to a computer

Question 23

Asynchronous serial data transmission

Answer 23

serial refers to a single wire being used to transmit bits of data one after the other
asynchronous refers to a sender using its own clock/timer device rather than sharing the same clock/timer with the recipient device

Question 24

High-definition multimedia interface (HDMI)

Answer 24

type of port connecting devices to a computer

Question 25

Video graphics array (VGA)

Answer 25

type of port connecting devices to a computer

Question 26

High-bandwidth digital copy protection (HDCP)

Answer 26

part of HDMI technology which reduces risk of piracy of software and multimedia

Question 27

Fetch-execute cycle

Answer 27

a cycle in which instructions and data are detected from memory, decided and finally executed

Question 28

Program counter (PC)

Answer 28

a register used in a computer to store the address of the instruction which is currently being executed

Question 29

Current instruction register (CIR)

Answer 29

a register used to contain the instruction which is currently being executed or decoded

Question 30

Register transfer notation (RTN)

Answer 30

short hand notation to show movement of data and instructions in a processor
can be used to represent the operation of the fetch-execute cycle

Question 31

Interrupt

Answer 31

signal sent from a device or software to a processor requesting its attention
the processor suspends all operations until the interrupt has been serviced

Question 32

Interrupt priority

Answer 32

all interrupts are given a priority so that the processor knows which need to be serviced first and which interrupts are to be dealt with quickly

Question 33

Interrupt service routine (ISR) and interrupt handler

Answer 33

software which handles interrupt requests and sends out the request to the CPU for processing