14.4 Initial System Loader

   

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If autoboot is on and you don't interrupt the boot process, ISL performs its intended tasks automatically. You can interact with the ISL by interrupting PDC. After interruption, when you use the boot command from the PDC menu, it gives you an option to interact with the ISL. At the ISL prompt you can use the commands shown in Table 14-1 to change the parameters in stable storage.

Table 14-1. The ISL Commands

Command	Description
display	Displays existing values
conspath	Modifies console path
primpath	Modifies primary boot path
altpath	Modifies alternate boot path
autoboot	Turns autoboot on or off
autosearch	Turns autosearch sequence parameters on or off

You can also use the setboot command on a running system to view or change these parameters. A typical output of the setboot command is shown next . You can use the setboot options to modify the parameters shown here.

 #  setboot  Primary bootpath : 0/2/0.6.0 Alternate bootpath : 7/2/0.6.0 Autoboot is ON (enabled) Autosearch is OFF (disabled) # 

Secondary Loader

As mentioned earlier, the boot block of the disk contains the LIF area where the secondary loader hpux is located. By default, the ISL reads the AUTO file in the LIF area to supply arguments to hpux . However, it is possible to run hpux at the ISL prompt and to provide different arguments to the command manually. If hpux is run without any argument, it loads /stand/vmunix from the primary boot devices. Let's see some important uses of hpux from a system administration point of view.

BOOTING ANOTHER KERNEL

You can have multiple HP-UX kernels on your system. If a new kernel does not work, use an alternate kernel for booting. For example, if you have an old kernel with name vmunix.old in the /stand directory, you can boot the system from that kernel with the following command at the ISL prompt.

 ISL>  hpux /stand/vmunix.old  

BOOTING IN SINGLE- USER MODE

To boot the system in single-user mode for system administration purposes, use:

 ISL>  hpux -is  

You may need to boot the system in single-user mode with a previous kernel if the new kernel does not work and you need to restore the old kernel. For this, you can use following command.

 ISL>  hpux -is /stand/vmunix.old  

The hpux command can also be used to list files in the /stand directory if you forget the name of the old kernel for booting purposes. You can also list files in the LIF area using hpux . Use of the hpux utility is summarized in Table 14-2.

Table 14-2. Use of the hpux Command

Command	Result
hpux	Loads /stand/vmunix from the primary boot path
hpux -is	Loads /stand/vmunix and boots in single-user mode from the primary boot path
hpux ll /stand	Lists files in the /stand directory
hpux show autofile	Displays the contents of the AUTO file
hpux set autofile < filename >	Sets new AUTO file with the contents of filename
hpux -v	Displays the version number of the hpux utility

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