Operating system (OS) is a set of programs that acts as an interface between user and computer hardware. It also manages the internal resources of a computer like control
Unit, arithmetic logic unit, memory unit, I/O unit etc. simply we can say that operating system (OS) is a communication channel between the user and the computer machine. It is must for any computer system because the OS is only:
The one program that runs at all the times on the computer.
The program that controls and co-ordinates the use of hardware among the various application program of various users.
An operating system is an integrated set of programs that is used to manage the various resources and overall operations of a computer system. It is designed to support the activities of the computer system.
Its prime objective is to improve the performance and efficiency of a computer system and increase its utility. Moreover, it makes the computer system user friendly, i.e. it makes it easier for people to interface with and make use of computer.
Operating systems go by many different names, depending on the manufacture of the computer. Other terms used to describe the operating system are executive, supervisor, controller and master control program etc.
The range of extent of services provided by an operating system depends on a number of factors. Various types of operating system are available with different features, characteristics and operational requirements. Some most popular OS are: MS-DOS, Windows NT,
Windows 9.x, Windows 2000/XP, UNIX, Linux, Mac OS etc.
Role of an operating system.
Why do we need a operating system ?
When a program is written in high level language and is executed by a computer, the following steps are involved: The user writes the program in the high-level language using an input device.
The source program is read and loaded in the memory.