Chapter Summary | HP Certified: HP-UX System Administration

HP-UX startup and shutdown processes are explained in this chapter. We started with an introduction to the startup process and listed the steps involved. The startup process can be divided into two major parts . The first part consists of steps that are performed by code that resides in ROM. This code is called processor dependent code (PDC) and is different for each model of server and workstation. The second part consists of processes that are performed by the operating system. This part starts with the Initial System Loader (ISL). The ISL loads the hpux utility, which in turn loads the HP-UX kernel, /stand/vmunix , into the memory. The kernel starts the swapper process, ioinitrc , and then the init process. The init process starts the server daemons and brings the system into the appropriate runlevel state. At shutdown time, the init process changes the runlevel to 0 and halts the system.

In brief, the following items are discussed in the chapter.

Processor dependent code (PDC) does a self-test and probes the hardware attached can be used to boot HP-UX in single- user mode.
PDC uses the Stable Storage Area to keep configuration information.
The to the system.
PDC menus can be used to search devices attached to the system and to specify primary and secondary boot devices.
PDC can be used to boot from a particular device.
PDC boot area of the disk is in LIF format and it contains the ISL and some utility programs.
The swapper process has process ID 0 and manages memory swapping.
The init process reads the /etc/inittab file for its configuration.
Runlevel is a state of the system that shows what services are available at a particular time. HP-UX is in one of eight runlevels at all times.
To add a program to be run at boot time, you place an execution script in the /sbin/init.d directory and its configuration file in the /etc/rc.config.d directory. You place links to the script in the sequencer directories. The sequencer directories have names like /sbin/rc n .d where n represents a runlevel.
The shutdown command gets help from the execution scripts called by their respective links in the sequencer directories to stop server daemons and halt the system. The reboot command kills these daemons and reboots the system. The /etc/shutdown.allow files show which users are allowed to execute the shutdown command.

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