casters-up mode [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]
