The computer's master control program ... most all computing devices no matter how small or large use an operating system in some form. THIS DEFINITION IS FOR PERSONAL USE ONLY.

but a 32-bit operating system will run in a 64-bit computer. See 64-bit computing. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission.

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 ...