System Power Management

System power management consists of turning off the entire computer after saving its state so that it can be returned to the same state immediately when it is turned back on.

To shut down an entire system and later return it to the state it was in prior to the shutdown, it is necessary to stop (and later restart) kernel threads and user processes, notify interested processes that the system has been suspended, and save (and later restore) the hardware state of all devices on the system. System power management is currently implemented only on some SPARC systems supported by the Solaris 7 software.

The Solaris System Power Management framework provides the following:

• A platform-independent model of system idleness

• System software to implement a system power management policy (which is controlled by a user-modifiable configuration file).

• A set of interfaces for the device driver to override the method for determining which drivers have hardware state. These interfaces are also used to determine how responsibility for saving the state is assigned.

• A set of interfaces to allow the framework to call into the driver to save and restore the device state, and a mechanism for notifying processes that a suspend or resume operation has occurred.