The Free On-line Dictionary of Computing (18 March 2015):
The principal inventor of the Unix operating
system and author of the B language, the predecessor of
In the early days Ken used to hand-cut Unix distribution
tapes, often with a note that read "Love, ken". Old-timers
still use his first name (sometimes uncapitalised, because
it's a login name and mail address) in third-person reference;
it is widely understood (on Usenet in particular) that
without a last name "Ken" refers only to Ken Thompson.
Similarly, Dennis without last name means Dennis Ritchie
(and he is often known as dmr).
Ken was first hired to work on the Multics project, which
was a huge production with many people working on it. Multics
was supposed to support hundreds of on-line logins but could
barely handle three.
In 1969, when Bell Labs withdrew from the project, Ken got fed
up with Multics and went off to write his own operating
system. People said "well, if zillions of people wrote
Multics, then an OS written by one guy must be Unix!". There
was some joking about eunichs as well.
Ken's wife Bonnie and son Corey (then 18 months old) went to
visit family in San Diego. Ken spent one week each on the
kernel, file system, etc., and finished UNIX in one month
along with developing SPACEWAR (or was it "Space Travel"?).
See also back door, brute force, demigod, wumpus.