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OPERATING SYSTEMS
1
WHAT IS AN OPERATING SYSTEM?
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An interface between users and hardware - an environment "architecture”.
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It is considered as the backbone of a computer managing both software and
hardware resources.
•
OS Provides Interface between the user and the hardware.
Architecture of Computer
System
Hardware
Operating System (OS)
Programming Language (e.g. PASCAL)
Application Programs (e.g. WORD, EXCEL)
Structure of Operating System:
USERS
Other System
Programs
Operating System
HARDWARE
Detail Layered View of
Computer
System Software, Application
Software and Driver Programs
•
System Software- Performs essential operation tasks
• Operating system
• Utility programs
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Application Software - Performs specific tasks for users
• Business application
• Communications application
• Multimedia application
• Entertainment and educational software
•
Driver Programs (Device Driver)
• small program that allows a specific input or output device to
communicate with the rest of the computer system
The Components of Operating System.
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1. Process Management
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2. Main Memory Management
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3. Mass Storage Management
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4. File Management
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5. Caching Management
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6.I/O Management
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7. Net Working Management
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8. Protection System
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9. Command - Interpreatersystem
Different OS Services
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User Interface
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Program Execution
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I/O Operations
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File-System Manipulations
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Communication
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Error detection
Three type of programs
• user / application programs
• programs used by the users to perform a
task
• system programs
• an interface between user and computer
• driver programs
• communicate I/O devices with computer
Basic functions of the operating
system
Device configuration
Controls peripheral devices connected to the computer
File management
Operating
System
Transfers files between main memory and
secondary storage, manages file folders, allocates
the secondary storage space, and provides file
protection and recovery
Memory management
Allocates the use of random access memory (RAM)
to requesting processes
Interface platform
Allows the computer to run other applications
Common Operating Systems
and Their Differences
• Network Operating System
• UNIX / Linux / MS Windows2000 Server
• Desktop Operating System
• MS Windows 9X/Me / Mac OS / DOS
• Mobile Operating System
• Palm OS and Pocket PC
Examples
• Common operating systems
• WINDOW
• used in IBM compatible microcomputers
• UNIX
• multi-user, multi-tasking OS used in
minicomputers and microcomputers
• VAX/VMS
• used in DEC’s VAX series of minicomputers
Different Types of Operating
System
UNIX
• 1970 Ken Thompson and Dennis Ritchie at at & TBell laboratory developed Unix Operating System.
• In 1973 ,It was re-written in ‘C’ Programming
language.
• How many types of Unix OS.
• Unbent
• Mint
• Red hat.
Unix System Architecture :
Standard Utility Program
and Users
Standard Library
UNIX OS
HARDWARE
VIEWS OF OPERATING SYSTEM
• .
VIEWS
USER
VIEWS
SYSTEM
VIEWS
• USER VIEW:- User view of the computer varies
by the interface being use. System which consist of a
monitor , keyboard , mouse and system units design
for one user to monopolize its resources.
• SYSTEM VIEW:- The operating system is the
program that is most intimate with the hardware . We
can view an operating system as a resource allocator.
STRUCTURE OF OPERATING SYSTEM
KERNEL
OPERATING SYSTEM
UTILITY SYSTEM
APPLICATIONS
• Kernel:-The kernel which is the care of os. The kernel
is also called real time executive. The kernel contains
all the devices that interact with the hardware.
• OPERATING SYSTEM:-Operating system controls
and coordinates the use of hardware among the
various applications programs for the various users.
• Utility system:- The system utilities are programs that
perform individual , specialized management tasks.
• APPLICATIONS :- Applications such as words
processor , spreadsheet , compilers define the way in
which these resources are used.
TYPES OF OPERATING
SYSTEM
Types of operating system is written in below:1.) Single user:- In this only one user can operate on single
operating system. For example “MS- DOS”
2.) MULTI USER :- In this multiple users can operate on single
operating system. A Multiuser operating system allows many
different users to take advantage of the computer resources
simultaneously.For example “ windows”
3.) BATCH SYSTEM:- In batch processing user can execute
programs in batch form . each batch contains similar type of
programs. batches are made by server and execute by
OPERATING
operating system
SYSTEM
USER
PROGRAM
AREA
4.)MULTI PROGRAMMING SYSTEM:-the operating
system keeps several programs in memory
simultaneously. it increases CPU utilization by
organizing job so that the CPU always has one to
executed.
Operating system
Job 1
Job 2
Job 3
Job 4
5.)PEER TO PEER SYSTEM:-in this different type of
systems are connected with straight line and first system
will be consider as a server and other systems are known
as a clients.
CLIENT 1
CLIENT 2
CLIENT 3
SERVER
CLIENT n
6.)Distributed System :- In distributed system is similar to a
client server architecture. Clients request the server for
their requirements and server would provide all services
that is needed to clients. It allows multiple application
program to cooperate to solve participate task.
7.) Real time:- real time consist all that time which is
required to the execution of the programs. Real time is of
two types that is hard time and soft time.
OPERATING
SYSTEM OVERVIEW
The Layers Of
A System
Humans
Program Interface
User Programs
O.S. Interface
O.S.
Hardware Interface/
Privileged Instructions
Disk/Tape/Memory
1: Operating Systems Overview
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Functions of Operating system
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•
•
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Process Management
Memory Management
File Management
Security management
Command Interpreter
1.Process management
• By process management OS
manages many kinds of activities :All process from start to shut down
Creation and deletion of user and
system processes.
2. Memory Management
• The major activities of an
operating regard to memorymanagement are:Decide which process are loaded into
memory when memory space becomes
available.
Allocate and deallocate memory space as
needed.
3.File Management
• The file management system
allows the user to perform such
tasks:Creating files and directories
Renaming files
Coping and moving files
Deleting files
4.Security Management
• By security management OS
manages many tasks such as:Alert messages
Dialogue boxes
Firewall
Passwords
5.Command Interpreter
• A command interpreter is an
interface between system and
the user. There are two types of
user interface:Command line
Graphical user interface
Contd……
• With a command line user interface
the user interact with the OS by typing
command to perform specific tasks
• With a graphical user interface the
user interacts with the OS by using a
mouse to access windows icons and
menus