IBM 6C4 - Manual (Page 77)

Service Processor Reboot/Restart Recovery
Reboot describes bringing the system hardware back up; for example, from a system
reset or power-on. The boot process ends when control passes to the operating system
process.
Restart describes activating the operating system after the system hardware is
reinitialized. Restart must follow a successful reboot.
Boot (IPL) Speed
When the system enters reboot recovery, slow IPL is automatically started, which gives
the POST an opportunity to locate and report any problems that might otherwise be
unreported.
Failure During Boot Process
During the boot process, either initially after system power-on or upon reboot after a
system failure, the service processor monitors the boot progress. If progress stops, the
service processor can reinitiate the boot process (reboot) if enabled to do so. The
service processor can re-attempt this process according to the number of retries
selected in the Reboot/Restart Policy Setup Menu.
Failure During Normal System Operation
When the boot process completes and control transfers to the operating system (OS),
the service processor can monitor operating system activity (see the Set Surveillance
Parameters option in the SERVICE PROCESSOR SETUP MENU). If OS activity stops
due to a hardware- or software-induced failure, the service processor can initiate a
reboot/restart process based on the settings in the Service Processor Reboot/Restart
Policy Setup Menu and the OS automatic restart settings (see the operating system
documentation).
If you are using the AIX operating system, the menu item under SMIT for setting the
restart policy is Automatically Reboot After Crash. The default is false. When the
setting is true, and if the service processor parameter
″ Use OS-Defined Restart Policy ″
is yes (the default), the service processor takes over for AIX to reboot/restart after a
hardware or surveillance failure.
Service Processor Reboot/Restart Policy Controls
The operating system’s automatic restart policy (see operating system documentation)
indicates the operating system response to a system crash. The service processor can
be instructed to refer to that policy by the Use OS-Defined Restart Policy setup menu.
If the operating system has no automatic restart policy, or if it is disabled, then the
service processor-restart policy can be controlled from the service processor menus.
Use the Enable Supplemental Restart Policy selection.
Chapter 3. Using the Service Processor 59