WordNet
disk operating system
n. an operating system that is on a disk [syn: DOS]
Wikipedia
Disk operating system
A disk operating system (abbreviated DOS) is a computer operating system that can use a disk storage device, such as a floppy disk, hard disk drive, or optical disc. A disk operating system must provide a file system for organizing, reading, and writing files on the storage disk.
Usage examples of "disk operating system".
MS-DOS stands for Microsoft Disk Operating System, an ancient operating system dating from 1981.
The boot disk bypassed the machine's Windows operating system and went straight to the leaner MS-DOS - the famous Microsoft Disk Operating System, which is the basis for the more user-friendly Windows.