What Post Diagnostics Do; What Post Error Messages Tell You - Sun Microsystems Sun Fire V490 Administration Manual

What POST Diagnostics Do

Each POST diagnostic is a low-level test designed to pinpoint faults in a specific
hardware component. For example, individual memory tests called address bitwalk
and data bitwalk ensure that binary 0s and 1s can be written on each address and data
line. During such a test, the POST may display output similar to this:
1:0>Data Bitwalk on Slave 3
1:0>
In this example, processor 1 is the master processor, as indicated by the prompt
1:0>, and it is about to test the memory associated with processor 3, as indicated by
the message "Slave 3."
Note – The x:y numbering system identifies processors that have multiple cores.
The failure of such a test reveals precise information about particular integrated
circuits, the memory registers inside them, or the data paths connecting them:
1:0>ERROR: TEST = Data Bitwalk on Slave 3
1:0>H/W under test = CPU3 Memory
1:0>MSG = ERROR:miscompare on mem test!

What POST Error Messages Tell You

When a specific power-on self-test discloses an error, it reports different kinds of
information about the error:
The specific test that failed
The specific circuit or subcomponent that is most likely at fault
The field-replaceable units (FRUs) most likely to require replacement, in order of
likelihood
80 Sun Fire V490 Server Administration Guide • August 2004
Test Bank 0.
Address: 00000030.001b0038
Expected: 00000000.00100000
Observed: 00000000.00000000