Consider a system composed of N nodes that can be faulty or fault-free.The purpose of system-level fault diagnosis is to have each fault-free node determine the state of all nodes of the system.Probabilistic diagnosis algorithm is very important in the system level fault diagnosis research.A system-level fault probabilistic diagnosis algorithm based on parallel group was proposed

PGSFPD algorithm

and the software emulation system of system-level fault diagnosis was presented.Experimental results are given through simulation of the algorithm for large systems of from 200 nodes to 1000 nodes under the emulation system.The results indicate the PGSFPD algorithm has better performance than the Somani Agrawal algorithm

which is a classic probabilistic algorithm in system level fault diagnosis.