Software Diagnostic Routine for Failing Chip Isolation
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Failing chips are identified in a defective field replaceable unit (FRU) by comparing the failing FRU with an identical good FRU. This can be done in any environment where these two FRUs can be plugged in identical processors and run in synchronization, such as the two processors in a dyadic machine. This comparison is done at machine speeds, thereby insuring valid AC testing and fault isolation. Each FRU contains many hardware-designed error checkers which check logic in their respective domains. These domains may overlap or cross FRU boundaries, and there may be logic which does not fall within any domain (unchecked logic). AC faults may occur only at machine cycle time and are dependent on the particular data that is being processed at the time.