Sun Microsystems SPARCclassic Service Manual page 29

NVRAM Parameters Used During POST and Boot Sequence
TABLE 2–1
NVRAM Parameter
selftest-#megs
Default = 1
diag-switch?
Default = False
auto-boot?
Default = True
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.
Description
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.
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.
When set to False, this will suppress the boot process.
The system halts with either the > prompt or the ok
prompt.
Troubleshooting Overview
15