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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 ?
In a related class of nonlinear effects, called hormesis, a compound at high doses has an inhibitory--and generally toxic--effect on some biological process but the opposite effect at certain low doses.
There were too few instances of virus with the K65R mutation in patients receiving the 200 mg dose to draw firm conclusions; however, the viral load reduction in patients with the K65R mutation treated with lower doses of Reverset suggests that the compound is also active against this mutation.
PA-457, the first-in-class maturation inhibitor, exhibits antiviral activity following a single oral dose in HIV-1-infected patients.
Low dose mifepristone and two regimens of levonorgestrel for emergency contraception: a WHO multicentre randomised trial, Lancet, 2002, 360(9348): 1803-1810.
REQUIRED DOSES: Kindergarten: 2 doses, both on or after 1st birthday.
99m]-pertechnetate to quantify salivary flow before and after cumulative doses of 170 to 270 mCi of [I.
For the same reason that doctors urge patients struggling against bacterial infections to complete any prescribed course of antibiotics, physicians prefer to hit HIV with steady doses of medication rather than with intermittent wallops.
The DES situation could be seen as a worst-case scenario for prenatal EDC exposure--the deliberate delivery of a potent estrogenic chemical in high doses.
Individual responses to different stimulant doses varied greatly, Evans notes.