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Power Saving Modes

The PowerBook computer meets the following energy saving standards:

Energy Saver
Energy Star (US)
Blue Angel (Germany)

To meet those standards, the default configuration of the computer must draw less than 7 watts in Sleep mode and less than 5 watts in off mode, while plugged into the AC adapter and with the battery removed.

The Power Manager has been redesigned to reduce power consumption in Sleep mode. The new version, Power Manager 2.0, is a native Mac OS manager designed to implement common power management policy across all Macintosh models by means of the new Power Plugin component. For information about API changes in Power Manager 2.0, refer to Technote 1190, Power Manager 2.0. The technote is available on the Technote website at

http://developer.apple.com/technotes/

With the new power management architecture, the following operating modes are defined:

Run Single: The processor is running at maximum processing capacity.
Idle: The system is idling with the main processor stopped in sleep mode. All clocks are running; the system can return to running code within a few nanoseconds. Cache coherency is maintained in this level of idle.
Sleep: The system is completely shut down, with only the DRAM state preserved for quick recovery. All processors are powered off with their state preserved in DRAM. All clocks in the system are suspended except for the 32.768 Khz timebase crystal on the PMU99 IC.

The computer automatically enters Idle mode after several seconds of inactivity. If the computer is attached to a network and an AC power supply, it is able to respond to service requests and other events directed to the computer while it is in Idle mode. The user can enable this by selecting Wake-on-LAN in the Energy Saver control panel.

The computer cannot respond to network activity when it is in Sleep mode. To prevent the computer from going into Sleep mode, the user must set the Sleep setting in the Energy Saver control panel to "Never."

Although the current public Power Manager interfaces will be maintained for application compatibility, this is a major revision that may affect developers. Information about the API changes for Power Manager 2.0 is available in a technote, which can be obtained from the website at

http://developer.apple.com/technotes/index.html