Chapter 4 - Operating systems and computer architecture

Question 1

Define Operating System

Answer 1

the software running in the background of a computer system - it manages many of the basic functions

Question 2

What is an interrupt?

Answer 2

a signal sent from a device (or other software) to the processor requesting its attention

Question 3

What is a buffer?

Answer 3

a temporary memory area in a device

Question 4

Define computer architecture

Answer 4

how a computer system is designed

Question 5

What do buses do?

Answer 5

buses move data around the computer and also send out control signals to synchronise the internal operations

Question 6

What are registers?

Answer 6

high-speed storage areas within the computer

Question 7

What is a memory unit made up of?

Answer 7

it is made up of addresses and contents

Question 8

What is a control unit?

Answer 8

it controls the operation of the memory, processor and input/output devices

Question 9

Give 5 examples of operations/tasks Operating Systems do

Answer 9

human-computer interface (HCI)
multitasking
multiprogramming
batch processing
error handling
load/run applications
management of user accounts
file utilities
processor management
memory management
real-time processing
interrupt handling
security
input/output control

Question 10

What are examples of devices that do not require an operating system?

Answer 10

ovens

washing machines

Question 11

Why do some devices not need an operating system?

Answer 11

they carry out simple, unchanging tasks which are initiated by a user pressing a button

Question 12

What do interrupts cause the processor to do?

Answer 12

temporarily stop what it is doing and service the interrupt

Question 13

Why are buffers used?

Answer 13

to compensate for the slower operating speed of peripherals when compared to a processor

Question 14

What do buffers allow processors to do?

Answer 14

to carry on with other tasks

Question 15

What is an example where buffers are used?

Answer 15

printers

music/video streaming

Question 16

What is the von neumann architecture?

Answer 16

a concept that holds programs and data in memory
data moves between the memory unit and processor
between processor, memory unit and input/output devices

Question 17

What does an address bus do?

Answer 17

carries signals relating to addresses between the processor and memory
uni-directional

Question 18

What does a data bus do?

Answer 18

sends data between the processor, memory unit and the input/output devices
bi-directional

Question 19

What does a control bus do?

Answer 19

carries signals relating to control and coordination of all activities within the computer, it can be uni-directional or bi-directional due to internal connections

Question 20

Where must data be represented before it is processed?

Answer 20

in registers

Question 21

What are 5 different types of registers in the von neumann architecture?

Answer 21

Memory address register (MAR)
Memory data register (MDR)
Arithmetic and Logic Unit (ALU)
Program counter (PC)
Current Instruction Register (CIR)

Question 22

What does a control unit do?

Answer 22

read instructions
interprets instructions
sends out signals along control bus to synchronise all computer components

Question 23

What does the fetch part of the fetch execute cycle entail?

Answer 23

the next instructions are fetched from the memory address stored in the PC
this is then stored in the CIR
the PC is incremented by so the next instruction can be processed

Question 24

What does the execute part of the fetch execute cycle entail?

Answer 24

the decoded instruction is then passed as a set of control signals to the appropriate components of the computer system