HP-UX System Administrator's Guide: Routine Management Tasks

Usually, the primary boot path points to the device from which you most frequently
boot and that device is available.
Once the boot device has been initialized, PDC (firmware routines) access a specially
formatted area on the boot device, called a LIF volume. PDC loads the Initial
System Loader (ISL) into memory and transfers control to it.
4. Kernel file selection: If uninterrupted (and if the autoboot flag is enabled -- See
“Automatic Versus Manual Booting” (page 58)) ISL will load and initiate the
HP-UX-specific boot loader hpux.
5. Load and initiate the HP-UX operating system: HP-UX uses the contents of the
AUTO file in the LIF area on the boot device to:
1. Locate the kernel file to boot.
2. Load the HP-UX kernel into memory.
3. Initiate the HP-UX kernel.
Typically, the AUTO file contains:
hpux vmunix
which tells hpux to load the kernel from the file called vmunix from the default
file system (/stand -- the file /stand/vmunix).
6. HP-UX goes through its initialization process and begins normal operation.
Automatic Versus Manual Booting
PDC sets up the boot and console devices using the Boot Console Handler (BCH).
Which actions the BCH takes once the console and boot devices have been initialized
depend on whether or not the operator manually interrupts an autoboot, and on the
state of two flags in nonvolatile memory: autoboot and autosearch.
Overriding an Automatic Boot
To override an automatic boot, hit any key on the console keyboard within the autoboot
delay period (usually 10 seconds). The Boot Console Handler will display its main
menu and allow you to interact with it.
Enabling / Disabling Autoboot
HP 9000 systems running HP-UX are usually set up to boot automatically when their
power is turned on. This is an important feature when systems are installed in locations
that are not always attended by an operator or system administrator. Should the power
fail at the computer site, the system can (usually) reboot itself without input from an
operator. The autoboot feature is also a convenience.
There are times when you do not want systems to automatically boot themselves, such
as when you want to boot from a different device or kernel file. See “Booting from an
Alternate Device” (page 65) or “Booting from an Alternate Kernel” (page 67).
58 Booting and Shutdown