The Free On-line Dictionary of Computing (30 December 2018):

Ken Thompson

    The principal inventor of the Unix operating
   system and author of the B language, the predecessor of
   C.

   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.

   (1999-01-26)