Concept of operating system:

An operating system is an essential software component of a computer system. The basic  objectives of an operating system are to make the computer system convenient to use and to utilize computer hardware in an efficient manner.  We can define an operating system as a large collection of software, which manages the resources of the computer system, such as memory, processor, file system and input/output devices. It keeps track of the status of each resource and decides which will have control over computer resources, for how long and when. In doing so, it provides two basic types of services:  

1.  It accepts requests from users and from the user's programs and executes their commands.  

2.  It optimally manages the hardware resources of the computer which may include CPU, main memory, hard disks, I/O devices, network interface card, etc.