MS-DOS: /M-S-dos/ n. [MicroSoft Disk Operating System] A
clone of CP/M for the 8088 crufted together in 6 weeks by
hacker Tim Paterson at Seattle Computer Products, who called the
original QDOS (Quick and Dirty Operating System) and is said to have
regretted it ever since. Microsoft licensed QDOS order to have
something to demo for IBM on time, and the rest is history.
Numerous features, including vaguely Unix-like but rather broken
support for subdirectories, I/O redirection, and pipelines, were
hacked into Microsoft's 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 appalling mess is now the
highest-unit-volume OS in history. Often known 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 360). The name further
annoys those who know what the term operating system does (or
ought to) connote; DOS is more properly a set of relatively simple
interrupt services. Some people like to pronounce DOS like "dose",
as in "I don't work on dose, man!", 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!"). See mess-dos,
ill-behaved.