MS-DOS

operating system /M S doss/ Microsoft Disk Operating System

(Or "DOS", "MS-DOG", "mess-dos") MicrosoftCorporation's clone of CP/M for the 8088 crufted

together in 6 weeks by hacker Tim Paterson, who is said to

have regretted it ever since.

MS-DOS is a single user operating system that runs one

program at a time and is limited to working with one megabyte

of memory, 640 kilobytes of which is usable for the

application program. Special add-on EMS memory boards

allow EMS-compliant software to exceed the 1 MB limit.

Add-ons to DOS, such as Microsoft Windows and DESQview,

take advantage of EMS and allow the user to have multiple

applications loaded at once and switch between them.

Numerous features, including vaguely Unix-like but rather

broken support for subdirectories, I/O redirection, and

pipelines, were hacked into MS-DOS 2.0 and subsequent

versions; as a result, there are two or more incompatible

versions of many system calls, and MS-DOS programmers can

never agree on basic things like what character to use as an

option switch or whether to be case-sensitive. The resulting

mess is now the highest-unit-volume operating system in

history. It is used on many Intel 16 and 32 bit

microprocessors and IBM PC compatibles.

Many of the original DOS functions were calls to BASIC (in

ROM on the original IBM PC), e.g. Format and Mode. People

with non-IBM PCs had to buy MS-Basic (later called

GWBasic). Most version of DOS came with some version of

BASIC.

Also know as PC-DOS or simply as DOS, which annoys people

familiar with other similarly abbreviated operating systems

(the name goes back to the mid-1960s, when it was attached to

IBM's first disk operating system for the IBM 360). Some

people like to pronounce DOS like "dose" or to compare it to a

dose of brain-damaging drugs (a slogan button in wide

circulation among hackers exhorts: "MS-DOS: Just say No!").

[Jargon File]

(1998-07-19)