Sun Microsystems Enterprise 250 Owner's Manual page 235

Which method or tool you use to diagnose system problems depends on the nature
of those problems:
If your machine isn't able to boot its operating system software, you need to run
POST and OBDiag tests.
If your machine is "healthy" enough to start up and load its operating system
software, you can use Solstice SyMON software and SunVTS software to diagnose
system problems.
If your machine is at a remote location, use RSC to diagnose problems remotely.
The following chart provides an overview of when to use the various diagnostic
tools to diagnose hardware problems.
Run OBDiag
no
OBDiag
failure
?
Software or
disk problem
no
Run POST
yes
no
POST
failure
?
yes
Chapter 11
System
yes
boots
?
yes
Fault
LED lit
?
Replace part
Diagnostics and Troubleshooting
no
Run SyMON
Run SunVTS
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