Note 7: Futurebus+ Mailbox Access Parity Error; Note 8: Multi-Event Analysis Of Command/Address Parity, Write-Data Parity, Or Read-Data Parity Errors; Sample System Error Report (Erf) - DEC 4000 AXP Service Manual

4.4.7 Note 7: Futurebus+ Mailbox Access Parity Error

Synopsis:
A data parity error occurred during reading of data from a Futurebus+ option via
a mailbox operation.
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.
4.4.8 Note 8: Multi-Event Analysis of Command/Address Parity,
Write-Data Parity, or Read-Data Parity Errors
Analysis:
Because command/address, read-data, and write-data share the backplane and
bus transverse, problems with these components can be seen as failures in any
of these cycles. It may be possible to identify the failing module by examining
several failure entries and drawing a conclusion as to the failing module.
• Are the parity errors always associated with the same responder?
If so, the fault is most likely with the responder.
• Are the read-parity errors always associated with the same commander?
If so, the fault is most likely with the commander.
• Is one module never reporting or associated with an error?
If so, this module could be corrupting the bus.

4.4.9 Sample System Error Report (ERF)

Example 4–1 provides an abbreviated ERF-generated error log for a processor
corrected machine check, SCB 630 ( ).
The low quadword of the error field, ERR FIELD LOW ( ), has one bit set. The
corresponding bit-to-text translation ( ) is provided in the third column.
The high quadword of the error field register, ERR FIELD HIGH ( ), has no bits
set.
4–16 Error Log Analysis