| Objective: Manage, monitor, and optimize system performance for mobile users. The chief issue with system performance for mobile users is that of managing power consumption on laptop computers when running on battery power. Microsoft provides the Control Panel Power Options applet for configuring several power management options that enable you to configure energy-saving schemes appropriate to your hardware. Windows XP provides the following two means of conserving power when a computer is not in use: Standby Saves configuration information in RAM, and turns off the computer's monitor, hard disk, and other system components. This state enables you to resume rapidly, but risks data loss should power be lost, for example when a laptop battery runs out. Hibernation Saves configuration information and data to the hard disk, and turns off all computer components. You need an amount of free hard disk space equal to the amount of RAM on the computer to save the entire contents of RAM. This state protects against power loss, but resuming operation takes longer from it than from standby.
Exam Alert Remember the difference between standby and hibernation If power is lost, data can be lost in standby mode because this mode does not save the desktop state to disk, only to RAM. You should use hibernation if there is a danger of power loss, whereas you should use standby if rapid resumption is more important. You can access the Power Options applet from the Performance and Maintenance section of Control Panel. This opens the dialog box shown in Figure 9.12. Available options depend on the computer's hardware. Consequently all the tabs shown in Figure 9.12 and discussed here may not be available. Figure 9.12. The Power Options Properties dialog box provides several options for configuring power management. Table 9.7 describes the functions of the various tabs in this dialog box. Table 9.7. Functions of the Tabs of the Power Options Properties Dialog BoxTab | Functions |
|---|
Power Schemes | Enables you to configure power schemes for different computer situations. In particular, you can configure power management schemes that conserve battery power on laptop computers. Such schemes turn off the monitor and hard disks after preset times of inactivity, and also enable you to configure the computer to enter standby or hibernation. | Advanced | Enables you to configure optional behavior, such as showing the icon on the taskbar or prompting for a password when the computer resumes from standby. You can also specify system behavior for when you press the computer's power button. | Hibernate | Configures the computer for hibernation and ensures that you have enough free disk space to enable hibernation. | APM | Configures the computer to use advanced power management (APM), which helps to reduce power consumption on portable computers and provides battery status information when running on battery power. | UPS | Enables the computer to work with an uninterruptible power supply (UPS). The computer communicates with the external UPS hardware to keep the system running until power is restored, the computer is shut down, or a low battery signal is received from the UPS. |
It is worth briefly mentioning the power schemes that are available from the Power Schemes tab of the Power Options Properties dialog box. Microsoft has supplied six preconfigured power schemes that help to strike a balance between usability and power conservation. You can edit one of these power schemes or create a new one if the preconfigured power schemes do not fulfill your needs. The preconfigured power schemes are as follows: Home/Office Desk Maintains power for all components except the monitor, which is turned off after 20 minutes of inactivity. Portable/Laptop Powers down all components after 5 to 30 minutes of inactivity. Designed for portable computers when running on battery power. Presentation Maintains power to the monitor as long as the computer is plugged in or running on battery power. Maintains power to all other components as long as the computer is plugged in. Always On Maintains power to all components of the computer indefinitely. Minimal Power Management Maintains power for all components except the monitor, which is turned off after 15 minutes of inactivity. Also disables certain power management features such as timed hibernation. Max Battery Conserves as much battery power as possible by turning off the monitor after 15 minutes. It does not turn the hard disks off.
On a computer that is equipped for Advanced Configuration and Power Interface (ACPI) power management, the available tabs and their appearance are somewhat different. Refer to Chapter 7 for information on ACPI and its configuration. You should note that APM is an older, less robust power management option than ACPI. Note Docking and undocking in standby You should not undock your machine when it is in standby or hibernate mode. It may lock up and cause data loss. Hot docking and undocking is supported only on machines configured with ACPI. Exam Alert Do not use standby when on a commercial airplane Airline regulations forbid the use of electronic devices during takeoff and landing. Because a computer on standby can wake to perform a scheduled task or other action, you should turn off your computer completely at these times. Managing Multiple Hardware Profiles for Laptop Users Portable computers may require different driver configurations depending on where they are used. You can configure hardware profiles in Windows XP that specify what drivers are loaded, for example when the computer is used on the road or when docked to a network connection in the office. In most cases, Plug and Play (PnP) technology enables Windows XP to detect the hardware configuration in use and choose the proper profile. If the computer is not fully PnP-compatible and Windows XP is unable to automatically detect the hardware for a given setting, you can create hardware profiles from which you can select at startup. Follow Step by Step 9.8 to create a hardware profile. Step by Step: 9.8 Configuring Hardware Profiles 1. | Open the System Properties dialog box and select the Hardware tab. | 2. | Click Hardware Profiles to display the dialog box shown in Figure 9.13. Figure 9.13. The Hardware Profiles dialog box enables you to create hardware profiles for different hardware configurations. | 3. | To create a new profile, select an available profile and click Copy. | 4. | On the Copy Profile dialog box, confirm the name provided or type a new name (for example, Undocked), and then click OK. | 5. | Select the new profile and click Properties. | 6. | On the dialog box that appears, select the check box labeled This Is a Portable Computer, and then select the appropriate docking option. To display the profile as a startup option, select the check box labeled Always Include This Profile as an Option When Windows Starts. Then click OK twice to exit the Hardware Profiles dialog box. | 7. | To configure the new hardware profile, restart the computer and select the new profile at startup. | 8. | Use Device Manager to modify the enabled state of hardware as required for this profile. We discussed the use of Device Manager in Chapter 7. |
|
The Hardware Profiles dialog box also enables you to set a timeout value for the menu that appears during the boot process for selecting hardware profiles. You should move the most typical profile to the top of the list, so that this profile is automatically selected should the user not select a profile within the listed timeout value. This reduces the probability of the wrong profile being started. Exam Alert You do not need a separate profile for a fully PnP-compliant computer used in a docking station You do not need to create a profile if the portable computer is being used at a docking station. You can simply select the This Is a Portable Computer option in the dialog box accessed in Step 6 of Step by Step 9.8. Review Break We have looked at several aspects of configuring portable Windows XP Professional computers for optimum performance and power usage under varying conditions. You should be aware of the following major points: Windows XP Professional provides a series of power management schemes tailored for different operating conditions. You can access these schemes from the Control Panel Power Options applet. You can configure a computer to enter standby or hibernation to conserve power as required. Standby saves operating data to memory and then powers down the hard disks, monitor, and other system components, whereas hibernation saves operating data to the hard disk and then powers down all computer components. Hardware profiles specify which hardware drivers are loaded under specified conditions, such as connected to the network or disconnected.
|
|