What is an Operating System (OS)?

Operating System (OS):

An operating system (OS) is a program that manages the computer hardware. It also provides a basis for application programs and acts as an intermediary between a user of a computer and the computer hardware. OS is an important part of every computer system.

 

 A computer system can be divided roughly into four components. These are:

1.  Hardware – the CPU, memory, and the input output devices provides the basic computing resources.

2.  Operating system – it controls and coordinates the use of hardware among the various  application programs for the various users.

3.   Application programs – such as word processors, spreadsheets, compilers and web browsers define the ways in which these resources are used to solve the computing problems of the users.

4.     Users – people who interacts with the system.

 

The following fig. shows an abstract view of a computer system.

An OS is similar to a government.  Like a government, it performs no useful function by itself.  It simply provides and environment within which other programs can do useful work. Operating systems can be explored from two view points:  the user and the system.

 

A more common definition is that the operating system is the one program running at all times on the computer usually called the kernel, with all else being application programs.