Hardware and Software Error Detection

1 INTRODUCTION A reliable computer system needs to provide its normal level of service in the presence of hardware and software faults [Avi86, Lap92]. There are two philosophies of achieving this reliability: fault avoidance, wherein techniques prevent the occurrence of faults in the first place, and fault tolerance, wherein techniques allow the system to continue execution despite the occurrence of faults. Fault tolerance can be implemented using one of two basic approaches: error masking, in which the system avoids the effect of an error through some form of majority voting, and error detection and recovery, in which the system has notices the presence of an error, locates and isolates the error, reconfigures in a spare, and restarts the system [Ren84].