• An operating system is a combined set of program that acts as an intermediate between user and computer hardware.
  • The primary goal of an operating system is to make the computer system easy to use efficiently.
  • The secondary goal is to manage the resource of a computer system.
  • Or we can say that an operating system is a program that acts as an interface between the user and the computer hardware and control and manages the overall resources of the computer system.

 POSITION OF OPERATING SYSTEM

  • The operating system is a very important component of the computer system.
  • Without the operating system, we have to write a long and complex command to perform every task. Which is very difficult to remember and it is very time taken process.
Example:-
1.  MS-DOS (Micro-soft disk operating system)
2.  CP/M (Control Program for Microprocessors)
3.  Windows:- two versions of Windows are:-
  • DOS with Windows
  • Windows NT
4.   OS/2
5.  Macintosh
6.  UNIX

Need for the operating system:-

  • Managing Input/Output unit.
  • Consistent user interface.
  • Multitasking.

The operating system as a resource manager

  • A software system is a vital part of an automatic data processing system.
  • The operating system is the resource manager. So, it can manage the resource of a computer system internally. The resource is a processor, memory, files, and device management.
  • As a resource manager, the four major functions of the operating system are:-

1.  Processor management:-

  • Keep track of the processor and status of the process. The program that does this is called a traffic controller.
  • Allocate the processor to a process.
  • Deallocate processor when the processor is no longer required.
  • In multiprogramming, it decides which process gets the processor when and how much time.

2.  Memory management 

  • It keeps track of primary memory it means what part of it is in use by whom, what part is not in use etc.
  • Allocates the memory when the process or program requests it to do so.
  • Deallocate the memory when the process no longer needs it or has been terminated.
  • In multiprogramming,  it decides that method can get memory once and the way a lot of.

3.  File management 

  • It keeps tracks of information, location, uses, status, etc.
  • Allocate resources.
  • Deallocates the resources.
  • Decide who gets the resources.

4.  Device management

  • Keeps tracks of all devices.
  • Efficiently allocates the device.
  • Deallocate device.
  • Decides that method gets the device once and for a way abundant time.