Boot Process in HPUX:
Boot process for PA-RISC and Integrity hardware is slightly different, the difference is the boot handler. In Pa-risc we use BCH as boot handler and in Integrity servers EFI.
PA-RISC Boot process
-------------------------
1. Poweron
2. POST/PDC (Processor Dependent Code) /IODC perform hardware self-tests and system initialization i.e it checks for cpu and memory and other peripheral connected to it.
3. BCH (boot console handler)consults NVRAM to identify the default boot device. Checks if AUTOBOOT Flag is on. If yes , its try to locate the Primary boot path.
4. Boot device/disk contains boot area with ISL utility, AUTO file and HPUX utility. isl/hpux use the auto file to choose and boot a kernel.
a. BCH loads Initial system loader , from Primary boot path.
b. ISL Loads the secondery loader called hp-ux.
c. hpux loads the kernel /stand/vmunix
5. vmunix/init complete the boot process.
a. kernel starts first process swapper , and then init
b. Shell /sbin/pre_init_rc executes .
c. init locates /etc/inittab
d. /etc/inittab starts the system the default run level , mentioned with "initdefault" parameter.
e. then executes /sbin/bcheckrc and activates LVM ,
Integrity Boot process :
1. Poweron
2. POST/PAL (Process Abstraction Layer)/SAL perform hardware self-tests and system initialization.
3. EFI (Extensible Firmware Interface) boot manager consults NVRAM to identify the default boot device. ---> main difference between pa-risc and integrity servers.
4. In boot disk there is a system partition with AUTO file and HPUX kernel loader.
5. hpux.efi uses the auto file to choose and boot a kernel
6. vmunix/init complete the boot process
Additional points :
Auto boot and Auto search:
PA-RISC Boot process
-------------------------
1. Poweron
2. POST/PDC (Processor Dependent Code) /IODC perform hardware self-tests and system initialization i.e it checks for cpu and memory and other peripheral connected to it.
3. BCH (boot console handler)consults NVRAM to identify the default boot device. Checks if AUTOBOOT Flag is on. If yes , its try to locate the Primary boot path.
4. Boot device/disk contains boot area with ISL utility, AUTO file and HPUX utility. isl/hpux use the auto file to choose and boot a kernel.
a. BCH loads Initial system loader , from Primary boot path.
b. ISL Loads the secondery loader called hp-ux.
c. hpux loads the kernel /stand/vmunix
5. vmunix/init complete the boot process.
a. kernel starts first process swapper , and then init
b. Shell /sbin/pre_init_rc executes .
c. init locates /etc/inittab
d. /etc/inittab starts the system the default run level , mentioned with "initdefault" parameter.
e. then executes /sbin/bcheckrc and activates LVM ,
Integrity Boot process :
1. Poweron
2. POST/PAL (Process Abstraction Layer)/SAL perform hardware self-tests and system initialization.
3. EFI (Extensible Firmware Interface) boot manager consults NVRAM to identify the default boot device. ---> main difference between pa-risc and integrity servers.
4. In boot disk there is a system partition with AUTO file and HPUX kernel loader.
5. hpux.efi uses the auto file to choose and boot a kernel
6. vmunix/init complete the boot process
Additional points :
Auto boot and Auto search:
Ø If we want our system automatically search for boot sources and
boot from prim/HAA or alternate boot path then both option should be on i.e
Ø If we want our system automatically search for boot sources
and list them but do not boot from any
of them automatically then auto search flag should be ON and auto boot flag OFF
Ø If we want our system automatically boot from primary boot source
but do not attempt to boot or list other boot sources is primary in unavailable
then auto search=OFF and auto boot=ON
Ø If we want manually supply a bootable device path and interact with
BCH each time our system is turned on
then set auto search=OFF and auto boot=OFF
Thanks...
Kirraan Jadhav
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