[IBM, probably from slang belly up] Yet another synonym for "broken" or "down". Usually connotes a major failure. A system (hardware or software) whICh is "down" may be already being restarted before the failure is notICed, whereas one whICh is "casters up" is usually a good excuse to take the rest of the day off (as long as you' re not responsible for fixing it). [Jargon File]