Section 5 Chapter 25 - Internal Computer Hardware

Question 1

Internal component

Answer 1

A component within the CPU

Question 2

External component

Answer 2

A component outside the CPU

Question 3

4 main internal components

Answer 3

• Processor
• Main memory
• Busses
• I/O Controllers

Question 4

Components of the processor (3)

Answer 4

• Control Unit
• ALU
• Registers

Question 5

Control unit

Answer 5

Coordinates and controls all the operations being carried out by the computer

Question 6

How the control unit operates

Answer 6

Fetch-decode-execute cycle

Question 7

Description of the fetch-execute-decode cycle

Answer 7

Fetch - causes the next instruction to be fetched from main memory
Decode - decodes the instruction
Execute - runs the instruction

Question 8

ALU

Answer 8

Performs arithmetic/logic operations on data

Question 9

Arithmetic operations

Answer 9

Addition, multiplication e.t.c

Question 10

Logical operations

Answer 10

> , =,

Question 11

Bitwise logical operations

Answer 11

AND, OR, NOT e.t.c.

Question 12

Register

Answer 12

A memory cell that operates at very high speed

Question 13

Bus

Answer 13

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

Question 14

The three main busses

Answer 14

• Control
• Address
• Data

Question 15

System bus

Answer 15

All the three main busses are system busses

Question 16

What it means when it’s said that a bus is a shared transmission medium

Answer 16

Only one device can transmit at any one time

Question 17

Which way can data flow on the busses

Answer 17

Control - 2 way
Address - 1 way (out of processor)
Data - 2 way

Question 18

Purpose of the control bus

Answer 18

To transmit command, timing and status information between system components

Question 19

Memory write (Control bus signal)

Answer 19

Data on the data bus is written to the address on the address bus

Question 20

Memory read (Control bus signal)

Answer 20

Data from the addressed location is loaded onto the data bus

Question 21

I/O Write (Control bus signal)

Answer 21

Data on the data bus is output to the addressed I/O port

Question 22

I/O Read (Control bus signal)

Answer 22

Data from the addressed I/O port is placed on the data bus

Question 23

Bus request (Control bus signal)

Answer 23

Indicates that a device is requesting to use the data bus

Question 24

Bus grant (Control bus signal)

Answer 24

Indicates the CPU has given access to use the data bus

Question 25

Clock (Control bus signal)

Answer 25

Used to synchronise operations

Question 26

Reset (Control bus signal)

Answer 26

Initialises all components

Question 27

Purpose of the data bus

Answer 27

A bi-directional path for moving data between system components

Question 28

How the data bus can affect performace

Answer 28

The width of the data bus (how many parallel wires) can affect performance, since it is how many bits can be simultaneously moved

Question 29

Word

Answer 29

A fixed size group of digits which is handled as a unit by the processor

Question 30

How words are fetched

Answer 30

Each word has it’s own specific address which can be referenced

Question 31

How the width of the address bus affects the system

Answer 31

The width determines the maximum possible memory capacity (although multiplexing can be used)

Question 32

How multiplexing is used with addressing

Answer 32

The address is sent in two equal parts following immediately after one another

Question 33

I/O controller

Answer 33

A device which interfaces between an input/output device and the processor. The controller will receive input/output requests from the processor and will then communicate these to the device using device-specific signals

Question 34

Components of an I/O controller (3)

Answer 34

• Interface that connects the controller to the system or I/O bus
• A set of data, command and status registers
• An interface that enables connection of the controller to the cable connecting the device to the computer

Question 35

Interface

Answer 35

A standardised form of connection defining things such as signals, number of connecting pins and voltage levels

Question 36

von Neumann machine

Answer 36

Both instructions and data are stored together in a single storage space

Question 37

stored program concept

Answer 37

Machine code instructions stored in main memory and executed serially by the processor

Question 38

Harvard architecture

Answer 38

The instructions and data are physically separated and stored in separate stores

Question 39

Where von Neumann architecture is used

Answer 39

General purpose computers

Question 40

Where harvard architecture is used

Answer 40

in embedded systems

Question 41

Advantages of Harvard architecture

Answer 41

Can be faster because data and instructions can be fetched at the same time as they each have a separate bus, also instructions can be held in ROM.

Question 42

Main memory

Answer 42

RAM

The main storage region of the computer to which the processor has direct access

Question 43

Processor

Answer 43

Where instructions and operations are carried out