Desperately sought just an extra 4K of RAM to see if a LISP expert system would get through a diagnosis on a Huge Aircrash Firefinder maintenance guide - had a kernel license, dug around and found a magic flag for a 4K block - tested it, seemed OK, put it out in the field, and the first time it ran, it grabbed that extra 4K and was instantly rewarded with a "Panic: out of swap space" and the whole damn thing dropped dead :-(