saving the current state of a program and its data, including intermediate results to disk or other non-volatile storage, so that if interrupted the program could be restarted at the point at which the last checkpoint occurred. This facility came into popular use in mainframeoperating systemsssuch asOs/360 in which programs frequently ran for longer than the mean time between system failures. If a program run fails because of some event beyond the program' s control (e.g. hardware or operating system failure) then the processor time invested before the checkpoint will not have been wasted. (1995-02-07)