What is an Operating System?

An operating system (OS) does exactly what the name states: It is software that operates a computer system!

Not all computers have had or required an operating system. Particularly simple computers, including the earliest models of both business computers and microcomputers, as well as very simple embedded computers, do not require an operating system. The computer embedded into a simple mass-market microwave oven, for example, only ever runs one program, does not have communications capabilities, does not multitask, and is never updated, and therefore does not need an operating system.

However, virtually all contemporary computer systems, including most online embedded devices, are sufficiently complex that they are equipped with an operating system.