Page 8 - DCAP403_Operating System

Sarabjit Kumar, Lovely Professional University Unit 1: Introduction to Operating System

Unit 1: Introduction to Operating System Notes

CONTENTS

Objectives
Introduction
1.1 Operating System: Meaning
1.2 History of Computer Operating Systems

1.3 Supervisor and User Mode
1.4 Goals of an Operating System
1.5 Generations of Operating Systems
1.5.1 0 Generation
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1.5.2 First Generation (1951-1956)
1.5.3 Second Generation (1956-1964)

1.5.4 Third Generation (1964-1979)
1.5.5 Fourth Generation (1979 – Present)
1.6 Summary
1.7 Keywords

1.8 Self Assessment
1.9 Review Questions
1.10 Further Readings

Objectives

After studying this unit, you will be able to:

Define operating system
Know supervisor and user mode
Explain various goals of an operating system
Describe generation of operating systems

Introduction

An Operating System (OS) is a collection of programs that acts as an interface between a user
of a computer and the computer hardware. The purpose of an operating system is to provide
an environment in which a user may execute the programs. Operating Systems are viewed as
resource managers. The main resource is the computer hardware in the form of processors,
storage, input/output devices, communication devices, and data. Some of the operating system
functions are: implementing the user interface, sharing hardware among users, allowing users
to share data among themselves, preventing users from interfering with one another, scheduling
resources among users, facilitating input/output, recovering from errors, accounting for resource
usage, facilitating parallel operations, organising data for secure and rapid access, and handling
network communications.

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