What Falls Under the Heading of System Management?

The types of operations that typically fall under the heading of System Management are power management and management of the system's thermal environment (e.g., temperature monitoring in the platform's various thermal zones and fan control). It should be stressed, however, that system management is not necessarily limited to these specific areas.

The following are some example situations that would require action by the SM handler program:

• A laptop chipset implements a timer that tracks how long it's been since the hard drive was last accessed. If this timer should elapse, the chipset generates an SMI (System Management Interrupt) to the processor to invoke the SM handler program. In the handler, software checks a chipset-specific status register to determine the cause of the SMI (in this case, a prolonged cessation of accesses to the hard drive). In response, the SM handler issues a command to the hard disk controller to spin down the spindle motor (to save on energy consumption).

• A laptop chipset implements a timer that tracks how long it's been since the keyboard and/or mouse was used. If this timer should elapse, the chipset generates an SMI to the processor to invoke the SM handler program. In the handler, software checks a chipset-specific status register to determine the cause of the SMI (in this case, a prolonged cessation of user interaction). In response, the SM handler issues a command to the display controller to dim or turn off the display's backlighting (to save on energy consumption).

• In a server platform, the chipset or system board logic detects that a thermal sensor in a specific zone of the platform is experiencing a rise in temperature. It generates an SMI to the processor to invoke the SM handler program. In the handler, software checks a chipset-specific status register to determine the cause of the SMI (in this case, a potential overheat condition). In response, the SM handler issues a command to the system board's fan control logic to turn on an exhaust fan in that zone.