I'll be darned if I can find the URL to the story, but it is a brilliant application of giving the customer what they wanted. The short of it is that when you

I'll be darned if I can find the URL to the story, but it is a brilliant application of giving the customer what they wanted. The short of it is that when you dropped back to the command line, early versions of DOS didn't clear the memory. That meant that the program really just went into stasis, but in practice it meant restarting; see, the program ran off the floppy then, so to save or load to another disk was tricky. Because memory would be executed from the same address, you could insert this disk with an empty executable that would get DOS to send execution to that address, which happens to be the program already in memory. This had the huge boon of allowing you to drop to the command line, do something, and the resume working! Apparently they sold the disks for like $5 (or pounds) each, and the customers were extremely pleased. And the programmer was got a kick out of having rather impressive return per byte written :)