Failure supervising method and apparatus

摘要

A failure supervising method and apparatus are disclosed. Simply with a WDT by which a system is interrupted after the WDT goes time out, the system would stop in a serious case where the failure cannot be recovered from by the interruption alone. A plurality of stages of WDTs are operatively interlocked, and the interlocked WDTs interrupt the system strongly progressively in each of the stages. A small failure recoverable by an interrupt is recovered by an interrupt, a middle failure not recoverable by other than a non-maskable interrupt is recovered by a non-maskable interrupt, and a serious failure not recoverable by other than reactivation is recovered by resetting the system.