One Tuesday morning, my code brought down 67 restaurants piloting the new point-of-sale (POS) system. I'd written the code to reformat the mainframe database

One Tuesday morning, my code brought down 67 restaurants piloting the new point-of-sale (POS) system. I'd written the code to reformat the mainframe database of menu items, prices, etc, to the format used by the store systems. I hadn't accounted for the notion that the mainframe would run out of disk space. When the communications jobs ran, a flock of 0-byte files were downloaded to the stores. When the POS systems booted with their 0-byte files, they were... confused. As were the restaurant managers. As were the level 1, level 2, vendor, and executive teams back at headquarters. Once we figured it out, we re-spun the files, sent them out, and the stores were back in business. I added a disk space check, and have done much better with checking my return codes ever since.