Halt and Catch Fire

    (HCF) Any of several undocumented and
   semi-mythical machine instructions with destructive
   side-effects, supposedly included for test purposes on several
   well-known architectures going as far back as the IBM 360.
   The Motorola 6800 microprocessor was the first for which
   an HCF opcode became widely known.  This instruction caused
   the processor to toggle a subset of the bus lines as
   rapidly as it could; in some configurations this could
   actually cause lines to burn up.

   [Confirm?]

   (1995-12-14)