What is an operating system?
An operating system is a program that acts as a mediator between a user and the computer hardware. The function of an operating system is to provide an environment in which a user can execute programs. The main goal of an operating system is thus to make the computer system convenient to use. A secondary objective is to use the computer hardware in an efficient manner.
An operating system is a significant part of almost every computer system. A computer system can be separated roughly into four components: the operating system, the hardware, the application programs, and the users. The operating system coordinates and controls the use of the hardware among the various application programs for various users.