LINUX

An operating system is the software responsible for exercising control and coordinate the use of hardware among various application programs and the various users. It is a trustee of the resources of system hardware.

In an informal definition is a system which consists of providing a controlled and orderly distribution of processors, memory devices and I / S among various programs competing for them.
Despite all that we use operating systems almost daily, it is difficult to define what is an operating system. In part, this is because operating systems perform two different functions.

Provide a virtual machine, ie an environment where the user can execute programs convenient way, protecting it from the details and complexities of the hardware. Manage computer resources efficiently.