The Jargon File (version 4.4.7, 29 Dec 2003):

eighty-column mind
 n.

    [IBM] The sort said to be possessed by persons for whom the transition from
    punched card to tape was traumatic (nobody has dared tell them about
    disks yet). It is said that these people, including (according to an old
    joke) the founder of IBM, will be buried ?face down, 9-edge first? (the
    9-edge being the bottom of the card). This directive is inscribed on IBM's
    1402 and 1622 card readers and is referenced in a famous bit of doggerel
    called The Last Bug, the climactic lines of which are as follows:


       He died at the console
       Of hunger and thirst.
       Next day he was buried,
       Face down, 9-edge first.

    The eighty-column mind was thought by most hackers to dominate IBM's
    customer base and its thinking. This only began to change in the mid-1990s
    when IBM began to reinvent itself after the triumph of the killer micro.
    See IBM, fear and loathing, code grinder. A copy of The Last Bug
    lives on the the GNU site at http://www.gnu.org/fun/jokes/last.bug.html.


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

eighty-column mind

    The sort said to be possessed by persons for whom the
   transition from punched card to paper tape was traumatic
   (nobody has dared tell them about disks yet).  It is said that
   these people, including (according to an old joke) the founder
   of IBM, will be buried "face down, 9-edge first" (the 9-edge
   being the bottom of the card).  This directive is inscribed on
   IBM's 1402 and 1622 card readers and is referenced in a famous
   bit of doggerel called "The Last Bug", the climactic lines of
   which are as follows:

     He died at the console
     Of hunger and thirst.
     Next day he was buried,
     Face down, 9-edge first.

   The eighty-column mind is thought by most hackers to
   dominate IBM's customer base and its thinking.

   See fear and loathing, card walloper.

   [Jargon File]

   (1996-08-16)