Sun Microsystems SPARCstation 5 Service Manual page 25

Table 2–1Table 2–1 contains a list of NVRAM parameters and explains their effect on
the power-up sequence. For more detailed information about NVRAM parameters,
see the OpenBoot Command Summary.
Note - At any point during the high-level OBP execution, you can abort the OBP
sequence and access the FORTH Monitor by pressing the Stop and "a" keys
simultaneously.
NVRAM Parameters Used During POST and Boot Sequence
TABLE 2–1
NVRAM Parameter
selftest-#megsDefault = 1
diag-switch?Default = false
auto-boot?Default = true
At the FORTH Monitor prompt, you can direct the system to boot the operating
system from a location that you specify, or you can execute a variety of additional
FORTH-based tests. See the OpenBoot Command Reference for a complete
description of the FORTH Monitor.
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 OBP testing if
diag-switch? is concurrently set to false. The
minimum is zero; the maximum is the amount
actually installed in the system. The default is a
1-megabyte test.
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.
When auto-boot? is set to true and
diag-switch? is set to false, diag-switch?
forces the system to boot from the device and file
specified in boot-dev and boot-file.
If auto-boot? is set to true and diag-switch? is
set to true, the system boots 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
sequence. The system halts with the ok prompt.
Troubleshooting Overview
11