Note 5: Data Delivered To I/O Is Known Bad; Note 6: Futurebus+ Dma Parity Error - DEC 4000 AXP Service Manual

The failing module is the CPU reporting the failure, except:
• If EV_SYN_1F (''CPU reported syndrome 0x1f'') or C3_SYN_1F (''C3 reported
syndrome 0x1f'') bits are set in the error field, known bad data was supplied
to the CPU from another source (either memory or the other CPU).
– If C3_MEM_R_ERROR (''CPU error caused by memory'') bit is set,
examine MEMn_UNCORR (''MEM_n Uncorrectable Error'') or MEMn_
SYNC_Error (''MEM_n Chip Sync Error'') to identify which memory was
the source of the error.
– If C3_OCPU_ADD_MATCH (''CPU error caused by other CPU'') is set, the
other CPU caused the error.
• If other error bits associated with the CPU reporting the error are also set,
there is a probability that the fault is associated with this CPU module.

4.4.5 Note 5: Data Delivered to I/O Is Known Bad

Synopsis:
IO_CB_UNCORR—I/O module received data identified as bad from system bus.
Analysis:
Check to see if the following bits are set for the error field:
MEMn_UNCORR (''MEM_n Uncorrectable Error'')
MEMn_SYNC_Error (''MEM_n Chip Sync Error'')
CPUn_XXXXXX errors (''CPU_n xxx... error'')

4.4.6 Note 6: Futurebus+ DMA Parity Error

Synopsis:
Either an address or data parity error occurred on the Futurebus+ while a DMA
data transfer was executing from a Futurebus+ option to memory (detected by
the I/O module).
Analysis:
The failing module could be either the I/O module or one of the Futurebus+
options. There is no way to isolate to the failing Futurebus+ module from the
error log.
Error Log Analysis 4–15