Configuring Energy Saver Preferences


All Macs capable of using Mac OS X can save energy while they are inactive by taking advantage of sleep mode. Using sleep mode, a typical Desktop computer uses between 13 and 30 watts, and a display made after the middle of 1999 uses between 8 and 13 watts. These numbers reflect the requirements to comply with the U.S. Environmental Protection Agency’s Energy Star program. Most Macs that can use Mac OS X comply with the Energy Star requirements, and all Apple displays made since the middle of July 1999 comply. Using the sleep mode is advantageous in two ways. The first benefit is that when waking from sleep the computer is usable sooner than from a cold start. Not only is the computer already powered on, but the sleep state keeps applications and documents open so that when you wake the computer, you can start work from where you left off. Second, the computer can still wake up via network or modem if configured to do so while in sleep mode.

Naturally, you can save even more energy by switching off your display when you leave your computer for a while. (You cannot switch off an Apple display that has the ADC connector without shutting down the computer.) While shutting down your computer would conserve even more energy, you would lose the quick start advantage.

The Energy Saver preference pane is divided into three panels: Sleep, Schedule, and Options. Their controls and settings let you determine when your computer sleeps and wakes. If your computer is a PowerBook or iBook, you can also set an option to show the battery status in the menu bar. The battery status option is not present on a Desktop Mac.

Sleep panel

Use the Sleep panel to adjust how much energy your computer saves by setting how long it remains inactive before going to sleep. As shown in Figure 13-16, you can set separate sleep timings for the whole system and the display, and choose whether to put the hard disk to sleep when possible.

Note

Installing a PCI card may prevent a Power Mac from going to sleep according to the timing for system sleep as set in Energy Saver Preferences. This behavior depends on the particular make and model of the PCI card. Some cards can be upgraded to eliminate this behavior. Even if the system can’t sleep, you can still set separate timings for display sleep and hard disk sleep.

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Figure 13-16: The Screen Saver button is a shortcut that opens the Screen Saver panel of the Desktop & Screen Saver preferences pane.

Schedule panel

The Schedule panel, shown in Figure 13-17, is used to configure the computer to start up and/or shut down or sleep automatically. The utility of the Schedule panel provides the convenience and assurance that a given system is on at a specified time and off at a specified time. By definition start up can mean either turn on or wake up. Selecting Start up the computer will enable you to select the frequency and what time the computer should start up. The frequency pop-up contains the following selections: Everyday, Weekdays, Weekends, and the days of the week. Selecting Shut Down enables you to specify when the computer shuts down. Shut Down is a pop-up menu, and you can select Sleep if a complete shutdown is undesired. As with the Start up option, the frequency pop-up menu contains frequency settings.

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Figure 13-17: Use the Schedule pane to set your computer to start up and shut down automatically.

Options panel

As shown in Figure 13-18, the Options panel’s principal function is to configure when your computer wakes from sleep. The ancillary function is to configure Mac OS X to restart the computer after a power failure.

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Figure 13-18: Use the Energy Saver preferences pane’s Option panel to specify wake options.

Options for portables

When used with iBook and PowerBook computers, Energy Saver provides a number of features intended to help road warriors improve the performance of their portable computers. The majority of these features are managed via a combination of two pop-up menus: Optimize Energy Settings and Settings for. The Optimize Energy Settings pop-up menu contains a number of predefined energy saver settings optimized by task, as well as the ability to specify a custom configuration of settings. As an example, the Apple supplied Presentations setting ensures the display will not black out and sleep, whether the PowerBook is using a power adaptor or is on battery. The Settings for pop-up menu allows you to apply your settings based whether you are running off the power adapter or the battery. Last, when administrating the Energy Saver preference pane on portables, the Options panel contains a processor performance pop-up menu. As the name implies, this menu enables you to increase and reduce the overall performance of the processor in the computer. The benefits of reducing processor performance include extended battery life and a reduction of operating temperature.

Starting sleep manually

Although Mac OS X puts your computer to sleep after a period of inactivity, you gain additional energy savings by putting it to sleep manually if you know that you won’t use it for a while. Some of the following methods may work on your computer:

  • Choose Sleep from the Apple menu. (The Sleep command is dim on a Power Mac with a PCI card that prevents system sleep.)

  • Press the Power key on a keyboard that has one. On an Apple Pro keyboard, which has no power key, press the Control and Eject keys at the same time. (The Eject key is in the upper-right corner of the numeric keypad.) After pressing Power or Control-Eject, a dialog appears asking whether you want to restart, sleep, cancel, or shut down. Click Sleep or press the S key.

  • Close the lid on a PowerBook or iBook.

  • Press the power button on the computer on newer Mac models — such as a Power Mac G5 or a Power Mac G4.

  • Press the power button on the display on newer Apple displays — such as an Apple Studio Display with LCD screen and USB ports or an Apple Cinema Display. (On other Apple displays, pressing the power button simply turns off the display.)

Waking up your computer

To make your Mac wake up, try the following methods:

  • Click the mouse button.

  • Press any key on the keyboard (the Caps Lock and function keys may not work for this purpose).

  • Open a PowerBook or iBook.

Battery status in the menu bar

If the Battery icon is showing in the menu bar, you can use it to monitor the condition of your computer’s battery. The appearance of the Battery icon indicates whether the computer is using or recharging the battery, and how much battery capacity remains, as detailed in Table 13-3.

Besides indicating the battery condition graphically, the Battery icon can report the battery condition in words. You can see this information by clicking the Battery icon and looking at the top of the menu that appears. If the computer is using the battery, the first item in the Battery menu reports the hours and minutes of life remaining. If the computer is charging the battery, the menu reports the hours and minutes until the battery is fully charged. You can show the hours and minutes or an equivalent percentage in the menu bar by choosing from the Show submenu of the Battery menu.

Table 13-3: Battery Icon Appearance

Battery icon

Meaning

Battery fully charged and computer operating on AC power

Battery charging and computer operating on AC power

Battery in use and partly depleted

No battery; computer operating on AC power

Tip

You can move the Battery status icon by pressing the z key and dragging the icon. Drag the icon left or right to change its position relative to other icons on the right side of the menu bar. Drag the icon off the menu bar to make it vanish.




Mac OS X Bible, Panther Edition
Mac OS X Bible, Panther Edition
ISBN: 0764543997
EAN: 2147483647
Year: 2003
Pages: 290

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