The computer's master control program. When a computer is turned on, a small "boot program" loads the operating system. Although additional system modules may be loaded as needed, the main part, known ...

The original operating system for IBM PC compatible computers. It is the basic for the current Windows operating system. When people use the term DOS, they are commonly referring to Microsoft DOS or ...

A system software component that is external to the operating system kernel. If the phrase is used to refer to the operating system itself, it is redundant because an operating system "is" software.