information system-software topic: operating system concepts
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INFORMATION SYSTEM-SOFTWARE
Topic: OPERATING SYSTEM CONCEPTS
OBJECTIVES
• To define the term Operating System
• To discuss the historic overview of O/S
• Types of Operating Systems
• Interpret the basic functions of Operating System
GOALS OF AN OPERATING SYSTEM
• To make the computer system convenient to use.
• To use the computer hardware in an efficient manner.
PURPOSE OF AN OPERATING SYSTEM
The purpose of an operating system is
to provide an environment in which a
user may execute programs.
Users
Application Programs
Operating system
Computer Hardware
Abstract view of the components ofa computer system
WHAT IS AN OPERATING SYSTEM?
An Operating System is an interface between user and hardware of a computer system.
WHAT IS AN OPERATING SYSTEM?
An Operating System is a system
software which may be viewed as an
organized collection of software
consisting of procedures for operating a
computer and providing an environment
for execution of programs.
OTHER DEFINITIONS
• An Operating System is a control program.
• An Operating System is similar to a Government.
• An Operating System can be defined as a Resource Manager.
HISTORICAL VIEW OF AN OPERATING SYSTEM
Early systems:
In the early systems, no Operating System
programs runs on a base machine.
HISTORICAL VIEW OF AN OPERATING SYSTEM
Simple Monitor:
Monitor programs were developed that
allowed users to “batch” their jobs
together, which constituted an
automatic job sequencing.
HISTORICAL VIEW OF AN OPERATING SYSTEM
Offline Operation:
As computers became more complex,
especially with regard to I/O device
management, offline operating systems
were developed that permanently
resided in memory and provided I/O
Control Services for user jobs.
HISTORICAL VIEW OF AN OPERATING SYSTEM
Buffering and Spooling:
More ways to overlap CPU with slower operations.
Buffering:- overlap computing with
I/O for same job.
Spooling:- overlap computing with
I/O for different jobs.
HISTORICAL VIEW OF AN OPERATING SYSTEM
Multiprogramming:• Multiprogramming was used as a
technique to enhance the throughput efficiency.
• Overlapping interleaving computing of different jobs.
• More than one job is “ready” at the same time.
SPOOLING:
DISK
CARD READER
LINE PRINTER
CPU
Different types of Multiprogramming Operating System
• Multitasking operating system
• Multiprocessing operating system
• Multi-user operating system
TIMESHARING AND REAL-TIME SYSTEMS
Timesharing system:
This executes commands of several users as they are entered, attempting to provide each user with a reasonably short response time to each command.
TIMESHARING AND REAL-TIME SYSTEMS
Real-time system:
It is designed to respond
quickly to external signals
such as those generated by
data sensors.
FUNCTIONS OF OPERATING SYSTEM
Memory management
Process management
Device management
Information management
Protection
Error Handling
FUNCTIONS OF OPERATING SYSTEM
Memory management
Process management
Device management
Information management
Protection
Error Handling
The o/s keeps track of the memory, what parts are in use and by whom.
FUNCTIONS OF OPERATING SYSTEM
Memory management
Process management
Device management
Information management
Protection
Error Handling
The o/s keeps track of The o/s keeps track of processors and the status processors and the status
of processes. It decidesof processes. It decides who will have a chance to who will have a chance to
use the processor.use the processor.
FUNCTIONS OF OPERATING SYSTEM
Memory management
Process management
Device management
Information management
Protection
Error Handling
The o/s keeps track of the devices,
channels, control units and decides what is an efficient way to allocate the device.
FUNCTIONS OF OPERATING SYSTEM
Memory management
Process management
Device management
Information management
Protection
Error Handling
O/S keeps track of the information, its location, use, status etc. and decides who gets use
of the resources, enforce protection requirements.
FUNCTIONS OF OPERATING SYSTEM
Memory management
Process management
Device management
Information management
Protection
Error Handling
An o/s is to protect the userAn o/s is to protect the user from unauthorized access from unauthorized access
of his files or data.of his files or data.And also it should protectAnd also it should protect
itself from usersitself from users
FUNCTIONS OF OPERATING SYSTEM
Memory management
Process management
Device management
Information management
Protection
Error Handling
An o/s must respond to errors by taking the appropriate actions.
FILE CONCEPT
File is a collection of related information.
It is named and is referred by its name.
Files are organized into directories for
easy access.
DIRECTORY STRUCTURE
ROOT D0
F1
D3D2
D21 D31
F311
F31F21
D1
D311
CLIENT-SERVER MODEL
User process(client process) sends the
request to a server process, which
when does the work and sends back
the answer.
CLIENT-SERVER ARCHITECTURE
CLIENT is an application that runs on a
personal computer or on a workstation
and relies on SERVER to perform some
operations such as managing files,
disk drives, printers or network traffic.
NETWORK OPERATING SYSTEM
The Software that enhances a basic
Operating System by adding Networking
Features.
Examples: Novell Netware, WINDOWS NT
DISTRIBUTED OPERATING SYTEM
Distributed operating system is one that looks to its users like an
ordinarily centralized operating system but
runs on multiple independent CPU’s. Key concept is TRANSPARENCY.
• Operating system is an essential component of system software which consists of procedures for managing computer resources.
• Operating system functions primarily includes Memory, Process,Device, File management.
SUMMARY:
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