OS BASICS

CSC- 103

A presentation by-

Shakila Mahjabin TonniFaculty,

Department of CSE, IUBAT

WHAT’S AN OS?

Types of Software

Software are of two types-

Application software MS Word, Outlook,Adobe Photoshop and so on.

System Software Different OS, UtilitySoftware

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WHAT’S AN OS?

An Operating System is a set of programs whichmanages the resources of a computer system,enabling them to utilize efficiently.

This is an interface between applications andhardware.

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Convenience

Makes the computer more convenient to use by providing a way of communication between hardware and applications.

Efficiency

Allows computer system resources to be used in an efficient manner

Ability to evolve

Permit effective development, testing, and introduction of new system functions without interfering with service

OPERATING SYSTEM OBJECTIVE

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LAYERS OF COMPUTER SYSTEM

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TASKS OF OPERATING SYSTEM

Program execution

Access to I/O devices

Controlled access to files

System access

Error detection and response

internal and external hardware errors

memory error

device failure

software errors

arithmetic overflow

access forbidden memory locations

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Accounting

collect statistics

monitor performance

used to anticipate future enhancements

used for billing users

Provide a user interface

Run programs

Manage hardware devices

Organized file storage

TASKS OF OPERATING SYSTEM

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Two types of User Interfaces : GUI, Command- Line Interface

USER INTERFACE

Most common interface Example- Windows, OS X, Gnome, KDE Uses a mouse to control objects Uses a desktop metaphor Shortcuts open programs or documents Open documents have additional objects Task switching Dialog boxes allow directed input

GRAPHICAL USER INTERFACE

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Older interfaceDOS, Linux, UNIXUser types commands at a promptUser must remember all commandsIncluded in all GUIs

Two types of User Interfaces : GUI, Command- Line Interface

USER INTERFACE

COMMAND LINE INTERFACES

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Many different applications are supported by OS.

System call : Provides consistent access to OS features

Share information between programs : For example, Copy and paste, Object Linking and Embedding

RUNNING PROGRAMS

Programs need to access hardware.

Interrupts : CPU is stopped, hardware device is accessed.

Device drivers control the hardware

MANAGING HARDWARE

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Organized storage

Long file names

Folders can be created and nested

All storage devices work consistently

ORGANIZING FILES AND FOLDERS

Provide services not included with OS

Goes beyond the four functions

Firewall, anti-virus and file/folder compression, screen saver, file archiving in removable media etc.

UTILITIES

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Real-time operating system

Very fast small OS

Built into a device

Respond quickly to user input

Example, MP3 players, Medical devices

TYPES OF OPERATING SYSTEMS

Single user/Single tasking OS

One user works on the system

Performs one task at a time

Example, MS-DOS and Palm OS

Take up little space on disk

Run on inexpensive computers

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Single-tasking

Operating System cannot be able to take control back from the running process/task/application

In case if a process call an I/O Instruction then Processor must wait for I/O instruction to complete before preceding

DEFINITIONS

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DEFINITIONS

Multi-tasking

Operating System can take control back from the running process and can give it to other. When one job needs to wait for I/O, the processor can switch to the other job

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Single user/Multitasking OS

User performs many tasks at once

Most common form of OS

Windows XP and OS X

Require expensive computers

Tend to be complex

TYPES OF OPERATING SYSTEMS

Multi user/Multitasking OS

Many users connect to one computer

Each user has a unique session

UNIX, Linux, and VMS

Maintenance can be easy

Requires a powerful computer

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THANK YOU!