Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Acronyms, Idioms, Wikipedia.


disk-operating system, often prefixed, as in MS-DOS and PC-DOS; a computer operating system


(computer science)


(operating system)
1. The common abbreviation for MS-DOS.

2. IBM's Disk Operating System.

3. Any disk operating system.


(1) See denial of service.

(2) (Disk Operating System) Any operating system that supports hard drives. See operating system.

(3) (Disk Operating System) A family of IBM mainframe operating systems (DOS, DOS/370, DOS/VS, DOS/VSE). As disk storage became accepted in the late 1960s, DOS started out as a variant of IBM's Tape Operating System (TOS); however, it was always the "junior partner" to OS/360 and its progeny. See DOS/VSE.

(4) (Disk Operating System)Pronounced "dahss." A single-user operating system from Microsoft for Intel x86 personal computers. It was the first operating system for IBM PCs and IBM-compatible PCs, and it remained the underlying control program for Windows 3.1, 95, 98 and ME. Subsequent versions of Windows incorporated all DOS functionality, and most DOS commands work the same in Windows. See cmd abc's.

The OS in the IBM PC was PC-DOS, and the OS used by all other PC makers was MS-DOS. Except for DOS 6, which contained different utilities, PC-DOS and MS-DOS commands and system functions were the same, and all PC-DOS and MS-DOS versions were commonly called "DOS." See DOS 6.

DOS Lives On
In various incarnations, DOS is still used in embedded systems, where a small OS footprint is required. Examples are Digital Research's DR-DOS, ROM-DOS from DataLight ( and the open source FreeDOS. See embedded system.
References in periodicals archive ?
The rest are either DOS (which can run on DOS or Windows 3.
If you can't justify the cost of a hardware changeover at this time, then choosing or staying with a DOS program may be the best answer - for now.
IQS Business System for DOS and Windows consists of 13 integrated software modules for ISO 9000 support, including one for calibration, documentation tasks, customer management, and supplier management.
A-Plus-Tax introduced its Windows version of the 1040 package this year, so now it has both a DOS and a Windows version.
GoSystem, as well as EasyGo--CLR's DOS product marketed to smaller firms--has extensive practice management tools.
IBM, which has kept pace with Microsoft through a competing version of DOS, caued PC-DOS, plans to keep the operating system alive.
IT DOESN'T MATTER whether your computer environment is DOS, Windows, Unix, OS/2, a network, a mainframe or a Macintosh.
Research conducted by the Departments of Defense and Health and Human Services--including all National Institutes of Health programs--would remain independent of any DOS.
A network with fewer than about 20 computers works reasonably well with DOS.
But Windows has drawbacks: Compared with DOS programs, it's slow.
Available products: Automenu, DOS 5, DR DOS, File Director, Magellan, Norton Commander, PC Tools, Power Panel, TakeCharge
These programs are inexpensive and easy to use because they are menu-driven and accomplish tasks that cannot be performed with DOS commands alone.