green card n.
[after the IBM System/360 Reference Data card] A summary of an assembly language, even if the color is not green and not a card. Less frequently used now because of the decrease in the use of assembly language. “I'll go get my green card so I can check the addressing mode for that instruction.”
The original green card became a yellow card when the System/370 was introduced, and later a yellow booklet. An anecdote from IBM refers to a scene that took place in a programmers' terminal room at Yorktown in 1978. A luser overheard one of the programmers ask another “Do you have a green card?” The other grunted and passed the first a thick yellow booklet. At this point the luser turned a delicate shade of olive and rapidly left the room, never to return.
In fall 2000 it was reported from Electronic Data Systems that the green card for 370 machines has been a blue-green booklet since 1989.