IBM Power 780 Technical Overview And Introduction page 190

Service processor
The service processor is a microprocessor that is powered separately from the main
instruction processing complex. The service processor provides the capabilities for the
following items:
POWER Hypervisor (system firmware) and Hardware Management Console
connection surveillance
Several remote power control options
Reset and boot features
Environmental monitoring
The service processor monitors the server's built-in temperature sensors, sending
instructions to the system fans to increase rotational speed when the ambient temperature
is above the normal operating range. Using an architected operating system interface, the
service processor notifies the operating system of potential environmentally related
problems so that the system administrator can take appropriate corrective actions before a
critical failure threshold is reached.
The service processor can also post a warning and initiate an orderly system shutdown in
the following circumstances:
– The operating temperature exceeds the critical level (for example, failure of air
conditioning or air circulation around the system).
– The system fan speed is out of operational specification (for example, because of
multiple fan failures).
– The server input voltages are out of operational specification.
The service processor can immediately shut down a system in the
following circumstances:
– Temperature exceeds the critical level or remains above the warning level for too long.
– Internal component temperatures reach critical levels.
– Non-redundant fan failures occur.
Placing calls
On systems without a Hardware Management Console, the service processor can place
calls to report surveillance failures with the POWER Hypervisor, critical environmental
faults, and critical processing faults even when the main processing unit is inoperable.
Mutual surveillance
The service processor monitors the operation of the POWER Hypervisor firmware during
the boot process and watches for loss of control during system operation. It also allows the
POWER Hypervisor to monitor service processor activity. The service processor can take
appropriate action, including calling for service, when it detects that the POWER
Hypervisor firmware has lost control. Likewise, the POWER Hypervisor can request a
service processor repair action if necessary.
Availability
The auto-restart (reboot) option, when enabled, can reboot the system automatically
following an unrecoverable firmware error, firmware hang, hardware failure, or
environmentally induced (AC power) failure.
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IBM Power 770 and 780 (9117-MMD, 9179-MHD) Technical Overview and Introduction