After Power Is Switched On - Sun Microsystems SPARCstation 4 110 Service Manual

After POST phase,
OpenBoot PROM firmware takes control
System initialization
Probe memory
Probe CPU
Stop-n
Yes
keys
pressed?
No
Setting nvram defaults
Stop-d
keys
pressed?
Set
No
use-
true
nvramrc?
Evaluate the
false
script
Probe SBus devices and
interpret their drivers
Install console
System banner
displayed on screen
FIGURE 2-2
2.2

After Power Is Switched On

When you turn on the system power, the low-level POST phase is initiated if any of
the following circumstances apply:
diag-switch? NVRAM parameter is set to true.
Stop-d keys are held down when you turn on the power.
Keyboard is disconnected, and diag-switch? is set to false.
Tests selftest-#megs
Yes
diag-switch?
Booting from diag-device=net B ooting from boot-dev=disk
and
diag-file
Normal
operating system
SunDiag System
Exerciser
Factory-Defined Boot Sequence—OpenBoot PROM Phase Settings and Tests
OpenBoot PROM Phase
Stop-a
Yes
keys
pressed?
No
diag-
false true
switch?
Tests all memory
true
mfg-
switch?
false
false
auto-
boot?
true
false
diag-
switch?
true
and boot-file
Press Stop-a to go to ok prompt
Chapter 2
Press Stop-a
to go to ok prompt
ok prompt
Boot <boot-device>
On-board
<boot-file>
diagnostics
Troubleshooting Overview 2-3