Halt and Catch Fire
<humour, processor> (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)