from
Jargon File (4.4.4, 14 Aug 2003)
green lightning
n.
[IBM]
1. Apparently random flashing streaks on the face of 3278-9 terminals
while a new symbol set is being downloaded. This hardware bug was left
deliberately unfixed, as some genius within IBM suggested it would let
the user know that `something is happening'. That, it certainly does.
Later microprocessor-driven IBM color graphics displays were actually
programmed to produce green lightning!
2. [proposed] Any bug perverted into an alleged feature by adroit
rationalization or marketing. "Motorola calls the CISC cruft in the
88000 architecture `compatibility logic', but I call it green
lightning". See also {feature} (sense 6).
from
The Free On-line Dictionary of Computing (8 July 2008)
green lightning
[IBM] 1. Apparently random flashing streaks on the face of
3278-9 terminals while a new symbol set is being downloaded.
This hardware bug was left deliberately unfixed, as some
genius within IBM suggested it would let the user know that
"something is happening". That, it certainly does. Later
microprocessor-driven IBM colour graphics displays were
actually *programmed* to produce green lightning!
2. [proposed] Any bug perverted into an alleged feature by
adroit rationalisation or marketing. "Motorola calls the CISC
{cruft} in the 88000 architecture "compatibility logic", but I
call it green lightning". See also {feature}.