microsoft disk operating system
(foldoc) | Microsoft Disk Operating System
Microsoft DOS
MS-DOS
/M S doss/ (Or "MS-DOS", "PC-DOS",
"MS-DOG", "mess-dos") Microsoft Corporation's clone of
the CP/M disk operating system 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 "/"). The resulting mess became the
highest-unit-volume operating system in history. It was
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 DOS, ignoring the fact that
there were many other OSes with that name, starting in the
mid-1960s with IBM's first disk operating system for the
IBM 360.
[Jargon File]
(2007-05-21)
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