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..
