GCOS:: /jee'kohs/ n. A {quick-and-dirty} {clone} of System/360 DOS that emerged from GE around 1970;

:GCOS:: /jee'kohs/ n. A {quick-and-dirty} {clone} of
System/360 DOS that emerged from GE around 1970; originally called
GECOS (the General Electric Comprehensive Operating System). Later
kluged to support primitive timesharing and transaction processing.
After the buyout of GE's computer division by Honeywell, the name
was changed to General Comprehensive Operating System (GCOS).
Other OS groups at Honeywell began referring to it as `God's Chosen
Operating System', allegedly in reaction to the GCOS crowd's
uninformed and snotty attitude about the superiority of their
product. All this might be of zero interest, except for two facts:
(1) The GCOS people won the political war, and this led in the
orphaning and eventual death of Honeywell {{Multics}}, and
(2) GECOS/GCOS left one permanent mark on UNIX. Some early UNIX
systems at Bell Labs used GCOS machines for print spooling and
various other services; the field added to `/etc/passwd' to
carry GCOS ID information was called the `GECOS field' and
survives today as the `pw_gecos' member used for the user's
full name and other human-ID information. GCOS later played a
major role in keeping Honeywell a dismal also-ran in the mainframe
market, and was itself ditched for UNIX in the late 1980s when
Honeywell retired its aging {big iron} designs.
-- The AI Hackers Dictionary