what is operating system and its types

 An operating system (OS) is software that manages computer hardware and software resources and provides commonservices for computer programs. The operating system is an essential component of the system software in a computer system. Application programs usually require an operating system to function.

Examples of popular modern operating systems include Android, BSD, iOS, Linux, OS X, QNX, Microsoft Windows, Windows Phone, and IBM z/OS. All these examples, except Windows, Windows Phone and z/OS, share roots in UNIX.