The Collaborative International Dictionary of English v.0.48:

Hal \Hal\ (h[^a]l), prop. n.
   Harold; -- a nickname.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

HAL \HAL\ (h[^a]l), prop. n.
   The name of an intelligent computer in the movie 2001,
   directed by Stanley Kubrick.
   [PJC]

The Free On-line Dictionary of Computing (19 January 2023):

HAL

   1.  HAL 9000, the murdering computer on the
   spaceship in the science fiction classic "2001, A Space
   Odyssey" by Arthur C. Clark.

   "HAL" is "IBM" with each letter changed to the one before
   and there is an unconfirmed rumour that 9000 is the sum of the
   various IBM computer numbers that were in service at the time.
   However, in the sequel "2010", Clarke emphatically denies that
   HAL's name is supposed to be "one step ahead of IBM".  It is,
   rather, short for "heuristic algorithm".

   2.  Hardware Abstraction Layer.

   (1995-11-09)