Chapter 2 Troubleshooting Overview 2-5
Note – At any point during the high-level POST, you can abort the POST process
and access the Forth Toolkit or system monitor by pressing the Stop and “a” keys
simultaneously.
If the auto-boot? parameter is set to false, the system proceeds to the Forth
Toolkit (ok prompt), or to the system monitor (> prompt). Using the Forth Toolkit,
you can direct the system to boot the operating system from a location that you
specify, or you can execute a variety of additional tests called On-Board Diagnostics.
See the Open Boot Command Reference for a complete description of the Forth Toolkit.
If the auto-boot? parameter is set to true (the default), the system boots a
standalone program. To determine which program and device to boot from, the
system checks the diag-switch? NVRAM parameter.
TABLE 2-2 summarizes the
effect of the auto-boot? and diag-switch? parameters.
TABLE 2-1 NVRAM Parameters Used During POST and Boot Sequence
NVRAM Parameter Description
selftest-#megs
Default = 1
This parameter determines how many megabytes of memory
to test during high-level POST. The minimum is zero; the
maximum is the amount actually installed in the system.
diag-switch?
Default = False
When set to True, this parameter forces the system to test
automatically all available memory. It also enables diagnostic
message output to serial port A. If a properly configured
terminal or “tip window” is connected, diagnostic progress
can be monitored through this port. Finally, a True setting
causes the system to boot the operating system from the
device and file specified in the diag-device and diag-
file NVRAM parameter fields.
auto-boot?
Default = True
When set to False, this will suppress the boot process. The
system halts with either the > prompt or the ok prompt.
TABLE 2-2 Summary of Autoboot and Diagnostic Switch Parameters
1
Autoboot Switch
Parameter
Diagnostic Switch
Parameter Result
False False or True > or ok prompt
True False Boot operating system from
device alias “disk” or “net”
for SPARCclassic X
True True Boot operating system from
device alias “net”
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