DEC: n. Digital Equipment Corporation. Before the {killer micro} revolution of the late 1980s,

:DEC: n. Digital Equipment Corporation. Before the {killer
micro} revolution of the late 1980s, hackerdom was closely
symbiotic with DEC's pioneering timesharing machines. The first of
the group of cultures described by this lexicon nucleated around
the PDP-1 (see {TMRC}. Subsequently, the PDP-6, {PDP-10},
{PDP-20}, PDP-11 and {VAX} were all foci of large and
important hackerdoms, and DEC machines long dominated the ARPANET
and Internet machine population. DEC was the technological leader
of the minicomputer era (roughly 1967 to 1987), but its failure to
embrace microcomputers and UNIX early cost it heavily in profits
and prestige after {silicon} got cheap. However, the
microprocessor design tradition owes a heavy debt to the PDP-11
instruction set, and every one of the major general-purpose
microcomputer OSs so far (CP/M, MS-DOS, UNIX, OS/2) were either
genetically descended from a DEC OS, or incubated on DEC hardware,
or both. Accordingly, DEC is still regarded with a certain wry
affection even among many hackers too young to have grown up on DEC
machines. The contrast with {IBM} is instructive.
-- The AI Hackers Dictionary