Chapter 1:
Introduction
What is an Operating System?
Mainframe Systems
Desktop Systems
Multiprocessor Systems
Distributed Systems
Clustered System
Real -Time Systems
Handheld Systems
Computing Environments
Operating System Concepts
1.1
Silberschatz, Galvin and Gagne 2002
What is an Operating System?
A program that acts as an intermediary between a user of
a computer and the computer hardware.
Operating system goals:
Execute user programs and make solving user problems
easier.
Make the computer system convenient to use.
Use the computer hardware in an efficient manner.
Operating System Concepts
1.2
Silberschatz, Galvin and Gagne 2002
Computer System Components
1. Hardware – provides basic computing resources (CPU,
memory, I/O devices).
2. Operating system – controls and coordinates the use of
the hardware among the various application programs for
the various users.
3. Applications programs – define the ways in which the
system resources are used to solve the computing
problems of the users (compilers, database systems,
video games, business programs).
4. Users (people, machines, other computers).
Operating System Concepts
1.3
Silberschatz, Galvin and Gagne 2002
Abstract View of System Components
Operating System Concepts
1.4
Silberschatz, Galvin and Gagne 2002
Operating System Definitions
Resource allocator – manages and allocates resources.
Control program – controls the execution of user
programs and operations of I/O devices .
Kernel – the one program running at all times (all else
being application programs).
Operating System Concepts
1.5
Silberschatz, Galvin and Gagne 2002
Mainframe Systems
Reduce setup time by batching similar jobs
Automatic job sequencing – automatically transfers
control from one job to another. First rudimentary
operating system.
Resident monitor
initial control in monitor
control transfers to job
when job completes control transfers pack to monitor
Operating System Concepts
1.6
Silberschatz, Galvin and Gagne 2002