At mainframe shops, where the computers have operators for
routine administrivia, the programmers and hardware people
tend to look down on the operators and claim that a trained
monkey could do their job. It is frequently observed that the
incentives that would be offered said monkeys can be used as a
scale to describe the difficulty of a task. A one-banana
problem is simple; hence, "It's only a one-banana job at the
most; what's taking them so long?"
At IBM, folklore divides the world into one-, two-, and
three-banana problems. Other cultures have different
hierarchies and may divide them more finely; at ICL, for
example, five grapes (a bunch) equals a banana. Their upper
limit for the in-house
sysapes is said to be two bananas and
three grapes (another source claims it's three bananas and one
grape, but observes "However, this is subject to local
variations, cosmic rays and ISO"). At a complication level
any higher than that, one asks the manufacturers to send
someone around to check things.