HP-UX System Administrator's Guide: Configuration Management

When you boot the system in fail-safe mode, the previous kernel configuration will be
automatically saved for you, with a configuration name something like
saved_3DE78FA0. The exact name will be printed for you in the boot messages on
the console.
When you boot the system in fail-safe mode, the boot will stop when you reach
single-user mode. At this time you should take any necessary steps to repair your
system or your configuration and then reboot onto a valid configuration. HP does not
recommend continuing to boot to multiuser mode after a fail-safe boot.
Modifying Tunable Values at Boot Time
Tunable values can be changed at boot time by putting tunable settings at the end of
the boot loader command line. These settings have the form tunablename=value,
with no embedded white space. The value must be an integer in either hexadecimal
(prefixed by 0x) or decimal. This value will replace the value saved in the configuration
being booted. (If the value is invalid, no change is made.)
For example, to change the value of nproc at boot time, do the following:
1. Boot the system and stop at the HPUX> (Integrity) or ISL> (HP 9000) prompt, as
described in “Booting a Saved Configuration” (page 198).
2. Execute the boot (Integrity) or hpux (HP 9000) command with optional options
and device file, followed by the tunable assignments, using the following syntax:
boot [option]... [devicefile] [tunable=value]...
hpux [option]... [boot] [devicefile] [tunable=value]...
For example, to boot the backup configuration and set nproc to 6000, the minimum
commands would be:
HPUX> boot backup nproc=6000
ISL> hpux backup/vmunix nproc=6000
200 Configuring the Kernel