Comparison of Parallel and Deductive Fault Simulation Methods

A comparison of the central processing unit (CPU) time and storage requirements for the parallel and deductive fault simulation techniques is presented. Versions of a parallel and deductive simulator were implemented and the comparison performed on an IBM System/360 Model 67 by simulating representative circuits including shift registers, sequencers, counters, two memory units, and a processor. The results indicate that the deductive technique requires less CPU time for "loosely sequential" circuits or circuits having large numbers of simulated faults (e.g., >1000). The parallel technique is faster for small (e.g., <500 gates) "highly sequential" circuits or for small numbers of simulated faults. The storage required for a parallel simulator, however, can always be less than that required for a deductive simulator. In general, if sufficient memory is available, the deductive simulator is the more cost-effective simulator when a wide range of circuits is to be simulated and only one type of simulator is available. A substantial savings in logic circuit development cost can be realized when the proper simulation technique is used for logic design verification, fault analysis, and the generation of diagnostic data.