Sun Microsystems SPARCstation 4, Service Manual

Page: 31 / 190

Chapter 2 Troubleshooting Overview 2-3
FIGURE 2-2
Factory-Defined Boot Sequence—OpenBoot PROM Phase Settings and Tests
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
.
Probe SBus devices and
interpret their drivers
use-
nvramrc?
After POST phase,
true
Evaluate the
script
Install console
System banner
displayed on screen
true
Yes
Tests all memory
false
true
true
true
false
false
Booting from
diag-device=net
Booting from boot-dev=disk
Normal
operating system
SunDiag System
Exerciser
Press Stop-a to go to
ok
prompt
ok
prompt
Boot < boot-device >
On-board
< boot-file >
diagnostics
false
OpenBoot PROM firmware takes control
false
System initialization
Stop-a
keys
pressed?
diag-
switch
?
No
mfg-
switch
?
auto-
boot?
diag-
switch?
to go to
ok
prompt
Press Stop-a
and
diag-file and boot-file
Tests
selftest-#megs
Probe memory
Probe CPU
Yes
No
No
Yes
Set
diag-switch?
Stop-n
keys
pressed?
pressed?
Stop-d
keys
OpenBoot PROM Phase
Setting
nvram
defaults