System Startup, Configuration, and Shutdown Reference Manual (32650-90907)

Chapter 3

System Startup Functions

Activating and Deactivating Autoboot and Autosearch Functions

Enabling and disabling the autoboot and autosearch flags determines one of four boot device and console

selections for system initialization. Hardware interprets the selections as follows:

Manual (autoboot off and autosearch off). Ask for the path to the boot device. Use the path that is indicated.

Initialize the path given, and boot from it.

Bootsearch (autoboot off and autosearch on). Search for a boot device. (Devices are searched from the

smallest to the largest physical address on the processor’s bus.) If the boot device has an incorrect data

format, search for the next boot device. If no boot device exists, or all have the incorrect data format, execute

manual selection.

Autoboot (autoboot on and autosearch off). Try to boot from the primary boot device specified in stable

storage. If the boot device does not exist or has an incorrect data format, execute manual selection. Once

booted, execute (performed by ISL) an autoboot file, which contains a command sequence, to bring up the

operating system without operator intervention. If the autoboot file does not exist, prompt the operator for

the utility command.

Autosearch (autoboot on and autosearch on). Try to boot from the boot device path stored in stable storage.

If the boot device does not exist or has an incorrect data format, execute the boot search selection. Once

booted, execute (performed by ISL) an autoboot file, which contains an autoboot sequence, to bring up the

operating system without operator intervention. If the autoboot file does not exist, prompt the operator for

the utility command.

To enable or disable these features, use the AUTOBOOT and AUTOSEARCH commands. Enter one or both of the

commands and the desired setting (ON/OFF) at the ISL prompt. The system responds with a message

indicating the flag status:

ISL> AUTOBOOT ON

Autoboot is ON (enabled).

ISL> AUTOBOOT OFF

Autoboot is OFF (disabled).

ISL> AUTOSEARCH ON

Autosearch is ON (enabled).

ISL> AUTOSEARCH OFF

Autosearch is OFF (disabled).

For more information on the autoboot and autosearch flags, refer to Appendix C, “Reading Stable Storage and

Nonvolatile Memory.”

Modifying Boot Paths in Stable Storage

The ISL commands PRIMPATH, ALTPATH, and CONSPATH are available for placing new primary boot path,

alternate boot path, or console boot path information in stable storage. The changes need to be in stable

storage to execute the autoboot sequence properly in the event of a power outage or other serious failure.