Manuals

Power Management Settings: Dell Latitude L400 User's Guide

Power Management Settings: Dell™ Latitude™ L400 User's Guide

	Experimenting With Power Conservation		Suspend-to-Disk Mode for Windows NT
	Using Key Combinations		Hibernate Mode for Windows 98, Windows 2000, and Windows Me
	Closing the Display		Power Management Properties for Windows 98
	Suspend Mode		Power Management Properties for Windows NT
	Standby Mode		Power Options Properties for Windows 2000 and Windows Me

Experimenting With Power Conservation

In general, the lower the value you set for each power conservation feature, the longer the battery's charge lasts. On the other hand, setting high values tends to optimize the computer's performance.

To evaluate the way that different settings affect how long you can operate the computer on battery power versus the relative efficiency of how the software performs, experiment as follows:

Use the computer with all the options set at their default values.
Use the computer with all the options disabled or set to Off.
Use the computer with all the options set to their minimum or maximum values.

NOTE: For Advanced Configuration and Power Interface (ACPI) compliant systems, power management settings, such as key combinations and standby or hibernate mode, are controlled exclusively by the Power Management Properties or Power Options Properties window in the Control Panel. See Power Management Properties for Windows 98 and Power Options Properties for Windows 2000 and Windows Me. In other operating systems, power management settings can be controlled from the Power screen in the system setup program.

Using Key Combinations

Table 1 identifies the power management key combinations.

NOTE: The key combinations in Table 1 can be used from an external keyboard by enabling the External Hot-Key option on the Advanced screen in the system setup program, and then pressing <Scroll Lock> instead of <Fn>.

Table 1. Key Combinations

Feature	Activate/Deactivate
Turn off display	To activate, press <Fn><F1>. To deactivate, move the cursor or press a key on the integrated or external keyboard. (If nothing happens, the computer may be in suspend or standby mode. Press the power button to resume normal operation.)
Suspend (or standby) mode	To activate, press <Fn><Esc>. To deactivate, press the power button.
Suspend-to-disk mode*	To activate, press <Fn><a>. (On a French keyboard, press <Fn><q>.) To deactivate, press the power button.
View battery status icon	Press <Fn><F3>.

* This key combination does not function under an operating system with the ACPI, such as Microsoft® Windows® 98, Windows 2000, or Windows Me.

Closing the Display

One way to conserve power on the computer is to close the display when the computer is not in use. When you close the display and an external monitor is not connected, the computer's display shuts off and, depending on how you set the Lid Close option on the Power screen in the system setup program, the computer may enter suspend mode (standby mode in Windows 98, Windows 2000, and Windows Me).

NOTE: If an external monitor is connected when you close the display, the computer does not activate suspend (or standby) mode. You can still use the external monitor.

To resume work, open the display. (The computer may take several seconds to resume operation.)

Suspend Mode

If your computer is running the Microsoft Windows NT® operating system, suspend mode stops almost all computer activity, but leaves the computer ready to resume operations immediately in about 20 to 30 seconds. Use suspend mode whenever you leave the computer unattended.

NOTICE: Windows NT saves data to random-access memory (RAM), not to your hard-disk drive, before entering suspend mode. If the computer enters suspend mode while running on battery power, data loss from RAM can occur if the battery discharges completely.

Suspend mode conserves battery power by turning off the microprocessor clock; the display; the hard-disk drive; the CD-ROM, DVD-ROM, or Zip 250 drive module (if installed); the external monitor connector; the external keyboard (if attached); the parallel port; the serial port; the touch pad; and the diskette drive.

You can enter suspend mode immediately by pressing <Fn><Esc> (or <Scroll Lock><Esc> on an external keyboard if the External Hot-Key option on the Power screen of the system setup program is enabled).

When you enter suspend mode, the power indicator is not lit.

Resume from suspend mode by pressing the power button. The computer may take several seconds to return to normal operation.

NOTES: On resumption from suspend mode, if a password is set, the computer displays the password prompt screen.

Suspend mode is known as standby mode under the Microsoft Windows 98 operating system.

Standby Mode

If your computer is running the Microsoft Windows 98, Windows 2000, or Windows Me operating system, standby mode turns off the display, stops the hard-disk drive, and turns off other internal devices so that the computer uses less battery power. When the computer resumes operation from standby mode, the desktop is restored exactly as it was before entering standby mode.

NOTICE: These operating systems save data to random-access memory (RAM), not to your hard-disk drive, before entering standby mode. If the computer enters standby mode while running on battery power, data loss from RAM can occur if the battery discharges completely.

You can enter standby mode by pressing <Fn><Esc>.To resume operation from standby mode, press the power button.

Suspend-to-Disk Mode for Windows NT

NOTE: The ACPI-compliant Windows 98, Windows 2000, and Windows Me operating systems use a similar feature called hibernate mode.

Suspend-to-disk (S2D) mode copies all system data to a reserved area—the S2D file—on the hard-disk drive and then turns off all power to the computer. When you resume normal operation, the same programs will be running and the same files will be open that were loaded before you activated this mode.

Place the computer in S2D mode if you intend to store the computer for a month or more. S2D mode preserves the configuration information stored in nonvolatile random-access memory (NVRAM). The reserve battery maintains this information, but it may run out of energy after about a month.

NOTE: S2D mode helps preserve system data by quickly saving it to the hard-disk drive if you are about to run out of battery power.

If the External Hot-Key option is enabled on the Power screen in the system setup program, you can enter S2D mode by pressing <Fn><a> (or <Scroll Lock><a> on an external keyboard). On a French keyboard, press <Fn><q> or <Scroll Lock><q>.

NOTE: These key combinations do not function under an operating system with ACPI, such as Windows 98, Windows 2000, or Windows Me.

Resume operation from S2D mode by pressing the power button.

Some PC Cards may not operate correctly after resuming from S2D mode. If you encounter problems with a card, remove and reinsert the card.

NOTE: Dell creates an appropriately sized S2D file before shipping the computer to you. Use the Suspend-to-Disk Utility to remove the file, to increase the size of the file, or to add the S2D file if you removed it. For information on creating a S2D file, see "Suspend-to-Disk Utility."

Hibernate Mode for Windows 98, Windows 2000, and Windows Me

NOTE: Hibernate mode is similar to the suspend-to-disk mode used with Windows NT.

Through the Power Options Properties (for Windows 2000 and Windows Me) or Power Management Properties (for Windows 98) in the Control Panel for ACPI-compliant systems, you can enable the computer's hibernate mode.

Hibernate mode copies everything in memory to the hard-disk drive and then turns off all power to the computer. When you resume normal operation, the same programs will be running and the same files will be open that were loaded before you activated this mode.

NOTE: Hibernate mode helps preserve system data by saving it to the hard-disk drive if you are about to run out of battery power.

To enable hibernate mode:

Click the Start button. Point to Settings and then Control Panel.
Double-click the Power Options (or Power Management for Windows 98) icon.

The Power Options Properties window appears.
Click the Hibernate tab.
Select Enable Hibernate Support.
Click Apply.
Click the Advanced tab.

In the options list on the Advanced tab, set one or more of the options to Hibernate as desired.
Click Apply.

When you shut down your computer, you will see a new option in the Start menu called Hibernate. See your operating system documentation or help for more information on hibernate mode.

Resume from hibernate mode by pressing the power button.

NOTICE: With systems running ACPI, you cannot remove devices or undock your computer while in hibernate mode.

Some PC Cards may not operate correctly after resuming from hibernate mode. If you encounter problems with a card, remove and reinsert the card.

Power Management Properties for Windows 98

Windows 98 provides the Power Management Properties window for setting power conservation features.

NOTE: Set timeouts and enable hibernate mode through the Power Management Properties window rather than through the Power screen in the system setup program.

To access the Power Management Properties window and set the power management features, perform the following steps:

Click the Start button, point to Settings, and click Control Panel.
Double-click the Power Management Properties icon.

The Power Management Properties window contains the following tabs:

Power Scheme — allows you to change individual power management settings or select one of three power mode settings (Always On, Home/Office Desk, or Portable/Laptop) that each provide a set of default power management settings.

Alarms — allows you to set the Low Battery and Critical Battery alarms to alert you when the battery charge falls below a certain percentage. When you received your computer, the Low Battery and Critical Battery alarm options were not checked. Dell recommends that you do not select these options.

Power Meter — allows you to view the percentage of battery life remaining when your computer is operating on battery power. If your computer is operating on AC power, the computer displays a message.

Advanced — allows you to display the Power Meter on the Windows 98 taskbar and to display a password prompt when the computer resumes operation from standby mode. Advanced also allows you to define the action of the Power buttons.

Hibernate — allows you to enable hibernate mode in Windows 98.

Power Management Properties for Windows NT

Dell provides Softex software compatible with the Power Management Controller, which allows you to suspend and resume your portable computer without affecting your ability to use the Dell Latitude L400 Advanced Port Replicator (APR).

Power Options Properties for Windows 2000 and Windows Me

The ACPI-compliant Windows 2000 and Windows Me operating systems provide the Power Options Properties window for setting power conservation features. By allowing you to create your own power schemes, the power options feature allows you to reduce the power consumption of your computer devices.

To access the Power Options Properties window and set the power management features, perform the following steps:

Click the Start button, point to Settings, and click Control Panel.
Double-click the Power Options Properties icon.

The Power Options Properties window contains the following tabs:

Power Scheme — allows you to select one of three power mode settings.

NOTE: With systems running ACPI, select the Notebook/Portable setting as the Power Scheme to conserve battery life while the system is in standby mode. If the Always On setting is selected, the battery life may be much shorter when in standby mode.

Alarms — allows you to set the Low Battery and Critical Battery alarms to alert you when the computer battery falls below a certain percentage. When you received your computer, the Low Battery and Critical Battery alarms check boxes were not checked. Dell recommends that you do not select these options.

Power Meter — allows you to view the percentage of battery life remaining when your computer is operating on battery power.

Advanced — allows you to specify the actions (standby, hibernate, or power off) of the power button, the sleep button, and closing the display. You can enable the hibernate mode through the Advanced tab.

Hibernate (ACPI only) — allows you to enable the hibernate feature.

See the Microsoft Windows 2000 Help for more information on Power Options Properties.

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