Sun Microsystems Netra T5220, Service Manual

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Chapter 1 Server Diagnostics 1-27
1.5 Running POST
Power-on self-test (POST) is a group of PROM-based tests that run when the server is
powered on or reset. POST checks the basic integrity of the critical hardware
components in the server (CPU, memory, and I/O buses).
If POST detects a faulty component, the component is disabled automatically,
preventing faulty hardware from potentially harming any software. If the system is
capable of running without the disabled component, the system will boot when
POST is complete. For example, if one of the processor cores is deemed faulty by
POST, the core will be disabled, and the system will boot and run using the
remaining cores.
1.5.1 Controlling How POST Runs
The server can be configured for normal, extensive, or no POST execution. You can
also control the level of tests that run, the amount of POST output that is displayed,
and which reset events trigger POST by using ALOM CMT CLI variables.
TABLE 1-7
lists the ALOM CMT CLI variables used to configure POST.
FIGURE 1-8
shows how the variables work together.
Note – Use the ALOM CMT CLI
setsc
command to set all the parameters in
TABLE 1-7
except
setkeyswitch
.
TABLE 1-7
ALOM CMT CLI Parameters Used for POST Configuration
Parameter Values Description
setkeyswitch normal
The system can power on and run POST (based
on the other parameter settings). For details see
FIGURE 1-8
. This parameter overrides all other
commands.
diag
The system runs POST based on predetermined
settings.
stby
The system cannot power on.
locked
The system can power on and run POST, but no
flash updates can be made.
diag_mode off
POST does not run.
normal
Runs POST according to
diag_level
value.