AS and A Level OCR Computer Science

PM Heathcote, RSU Heathcote, PG Online

Chapter 2 Systems software - all with Video Answers

Educators

Section 7

Functions of an operating system

01:26

Problem 1

(a) An operating system uses interrupts which have priorities.
Describe the sequence of steps which would be carried out by the interrupt handler when an interrupt is received and handled.
(b) The operating system of a personal computer supports multi-tasking. One of the operating system functions is memory management.
Describe two different strategies which could be used to manage the available memory.

James Kiss

Numerade Educator

01:29

Problem 2

(a) An operating system uses scheduling. One method of scheduling is first come, first served.
(i) Explain why the first come, first served scheduling method may not be efficient.
(ii) Describe one other scheduling method.
(iii) Explain why scheduling is necessary.
(b) Explain why memory management is necessary.
(c) Paging may be used in memory management. Describe paging.

James Kiss

Numerade Educator

01:38

Problem 3

(a) Describe what is meant by
(i) an interrupt
(ii) a buffer
(b) A computer system includes a printer.
(i) Explain the role of the printer buffer in the transfer of a job from the computer to the printer.
(ii) Explain why an interrupt is necessary during the transfer of data from the computer to the printer.

Adam Conner

Numerade Educator