Diagnosis of multiprocessor systems under failure of more than half processors

The possibility of diagnosis of the multiprocessor systems under multiple, up to n−2, failed processors within the framework of the Preparata–Metze–Chien model and method was analyzed. The complete system diagnosis, that is, determination of the good–failed state of all processors, is sometimes possible using the proposed method of analysis of the system diagnostic graph. More precisely, the conditions were determined for impossibility of system diagnosis.