OPERATING SYSTEM PART-2

                                                                                                                                                                                                                                              CLASSIFICATION & FUNCTION                                                                                                                                                                                          

 Operating system is primarily concerned with allocating and deallocating computer resources to one or more jobs. In fact, it can be looked upon as a cover on the hardware. Thus an OS is an important part of every computer system.

Operating system that supports a single user at a time is a single user operating system, such as Window XP. Some like LINUX, UNIX etc. support multiple users at a time.

          

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An operating system performs the following functions: 

Processor Management  

Memory Management

Input / Output Management

File Management 

Scheduling 

Time sharing

Security Management

                                                                                                                                                                           
Brief the following: -

Processor Management 

  The operating system assigns processors (if a computer has more than one processor ) to the different tasks that must be performed by the computer system.

Memory Management

Its (OS) allocates the main memory and secondary memory to the system programs, user programs & data.

Input / Output Management

  It carries out the input/ output management and co-ordinate and assigns different input and output devices.

File Management 

 It manages files on various storage devices and transfer of these files from one storage device to another. It also allow all files to be easily changed and modified through the use of text editors or some other file manipulation software packages. 

Scheduling 

    It establishes and enforces the job priority. That is, it determines and maintains the order in which jobs are to be executed in the computer system.                                                                                     

 Time sharing

 It co-ordinates and assign compilers, assemblers,utility programs, and other software packages to various users working on the computer system.

Security Management

It establishes data security and integrity. That is , it keeps different programs and data security and data in such a manner that they do not interfere with each other. Moreover, it also protects data from being destroyed by wrong user.

     

               

Four Categories of Operating System:-                                           

Single User Operating System :

Operating System which allows only on user to work on a computer at a time is known as single user operating system .

Example :  DOS , WINDOW XP etc.

Multi User Operating System:

A Multiuser operating system allow a number of user to work together on a single computer. Each User will be provided a terminal connected to a single computer.
Example : LINUX  , UNIX, WINDOW 2000  etc.

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Single Tasking Operating System:

Operating system which can execute only a single job / program at a time is known as single tasking operating system. 

Example : MS-DOS .

Multi Tasking Operating System

Multi tasking operating system supports execution of more than one job at a time.Most of today's operating systems, such as Window 2000, OS/2, UNIX , LINUX etc. support multi tasking.