Sun Microsystems Sun Fire V490 - Manual (Page 109)

Chapter 6 Diagnostic Tools 81
Here is an excerpt of POST output showing another error message.
CODE EXAMPLE 6-1 POST Error Message
Identifying FRUs
An important feature of POST error messages is the H/W under test line. (See the
arrow in
CODE EXAMPLE 6-1 .)
The H/W under test line indicates which FRU or FRUs may be responsible for the
error. Note that in
CODE EXAMPLE 6-1 , three different FRUs are indicated. Using
TABLE 6-13 to decode some of the terms, you can see that this POST error was most
likely caused by a bad system interconnect circuit (Schizo) on the centerplane.
However, the error message also indicates that the PCI riser board (I/O board)
may be at fault. In the least likely case, the error might stem from the master
processor, in this case processor 0.
Why a POST Error May Implicate Multiple FRUs
Because each test operates at such a low level, the POST diagnostics are often more
definite in reporting the minute details of the error, like the numerical values of
expected and observed results, than they are about reporting which FRU is
responsible. If this seems counter-intuitive, consider the block diagram of one data
path within a Sun Fire V490 server, shown in
FIGURE 6-3 .
FIGURE 6-3 POST Diagnostic Running Across FRUs
0:0>Schizo unit 1 PCI DMA C test
0:0> FAILED
0:0>ERROR: TEST = Schizo unit 1 PCI DMA C test
0:0>H/W under test = Motherboard/Centerplane Schizo 1, I/O Board, CPU
0:0>MSG =
0:0> Schizo Error - 16bit Data miss compare
0:0> address 0000060300012800
0:0> expected 0001020304050607
0:0> observed 0000000000000000
0:0>END_ERROR
Processor
I/O
bridge
Data
switch
PCI
controller
5-way
CPU / Memory board Centerplane PCI riser board
data
switch