microsoft dos

Microsoft Disk Operating System
Microsoft DOS
MS-DOS

   <operating system> /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)