The boot process on an HP 9000 system can be reduced in its simplest form to three steps. I'll provide a quick description of the three steps and then we'll take a look at some example boot processes so we can see these three steps in action. The following is a description of the three steps:
PDC
HP 9000 systems come with firmware installed called Processor Dependent Code (PDC - man page pdc). After the system is powered on or the processor is RESET, the PDC runs self test operations and initializes the processor. PDC also identifies the console path so it can provide messages and accept input. PDC would then begin the "autoboot" process unless you were to interrupt it during the 10-second interval that is supplied. If you interrupt the "autoboot" process, you can issue a variety of commands. The interface to PDC commands is called the Boot Console Handler (BCH.) This is sometimes a point of confusion; that is, are we issuing PDC commands or BCH commands? The commands are normally described as PDC commands and the interface through which you execute them is the BCH.
ISL
The Initial System Loader (ISL - man page isl) is run after PDC. You would normally just run an "autoboot" sequence from ISL; however, there are a number of commands that you could run from the ISL prompt.
hpux
The hpux utility manages loading the HP-UX kernel and gives control to the kernel. ISL can have hpux run an "autoexecute" file, or commands can be given interactively. In most situations, you would just want to automatically boot the system; however, we'll take a look at some of the hpux commands you can execute. This is sometimes called the Secondary System Loader (SSL.)
I find that there is a lot of confusion related to the boot process for new system administrators. To begin with, there is not much documentation that comes with new systems related to HP 9000 boot. Secondly, without any background on the boot process, it is difficult to determine at which phase of the boot your system is at any given time. Table 3-3 shows some system states and the corresponding prompts you can expect for each state in roughly the order you might see them at the time of system boot:
Table 3-3. /sbin/set_parms Arguments
Boot State of System
Prompt
Boot Console Handler (BCH)
Seen when you discontinue boot within 10 seconds. Used to perform PDC-related work.
Main Menu: Enter command or menu >
Initial System Loader (ISL)
Seen after PDC-related work.
ISL>?
hpux
Prompt varies. You usually issue hpux command at ISL prompt to boot. This is sometimes called the Secondary System Loader (SSL).
Varies depending on the state of the system.
Guardian Service Processor (GSP)
Seen when you type ^b (control b) to get access to GSP.
GSP>
There is only one way to describe the boot process and that is through example. The boot of a system with minimal hardware will be covered in the upcoming sections. I choose the boot of a system with minimal hardware so as not to get bogged down in hardware-related details, but to instead focus on the boot process. The messages supplied as a result of booting this modest system will allow us to focus on the boot process rather than on the many hardware components. The boot process consists of mostly the same steps for any HP 9000, so you can apply this information to your system. It may be, however, that you have a much larger system with more components that will produce more lengthy boot messages.
