overflow bit = O = overrun
overflow pdl n.
[MIT] The place where you put things when your PDL is full. If you don't have one and too many things get pushed, you forget something. The overflow pdl for a person's memory might be a memo pad. This usage inspired the following doggerel:
Hey, diddle, diddle
The overflow pdl
To get a little more stack;
If that's not enough
Then you lose it all,
And have to pop all the way back.
—The Great Quux
The term `pdl' (see PDL) seems to be primarily an MITism; outside MIT this term is replaced by `overflow stack' (but that wouldn't rhyme with `diddle').
--The Jargon File version 4.3.1, ed. ESR, this entry manually entered by rootbeer277.