Power Conservation

C H A P T E R 3

Software Modiﬁcations

performance or provide better conservation. The controls revert to the single slider if you click the Easy control. The PowerBook Control Panel remembers the state in which the controls were left when last used.

Figure 3-2PowerBook Control Panel

There are two modes of battery conservation. One is used when the PowerBook Duo 250 computer is plugged into AC main power, and the other is used when the computer is running on its battery. A TimeMgr task installed by an init in the PowerBook Duo ﬁle can automatically change the power management settings based on the machine environment.

When the PowerBook Duo 250 computer is shipped, the power conservation settings in the PowerBook control panel, shown in Figure 3-2, are set with the default settings for Battery and Power Adapter enabled. If you are using Easy mode, the settings used will be the default settings, and you will not be able to edit them. If you are in Custom mode, you can enable or disable automatic conservation, modify both Battery and Power Adapter, or revert to the default settings. To modify the settings, you may choose the set of parameters you wish to change (Battery or Power Adapter) through the pop-up menu, and adjust the sliders. The Power Manager is then reconﬁgured and the settings stored in the Preferences ﬁle.

At certain times, the PowerBook control panel compares the current Power Manager settings with both sets of parameters. It does this during open and activate events, when you switch from Manual to Auto Power Conservation, and when you switch to Custom view. If a match is found, the name of the matching set is displayed in the pop-up menu, and both the menu and the default button are active. If no match is found, No Set Selected is shown in the pop-up menu, and both menu and default button are inactive. Once a valid set is selected, No Set Selected is removed from the pop-up menu.

18	PowerBook Duo 250 Control Panels