This scenario covers managing power on Windows XP client computers using Group Policy Preferences. Let’s cover how Windows XP manages power before we cover Group Policy Preferences Power Management.

Windows XP Power Management

Windows XP only has one active power scheme for the entire computer and that scheme is based on the current or previously logged on user—that is to say Windows XP power schemes are only user-based. This means the power scheme can change as each user logs on. Also, it means that last logged on user’s power settings are the settings that remain once the user logs off. And yes, each user has its own power configuration; however, the entire operating system only has one active power scheme.

A recently started computer at the logon prompt makes the power configuration from the .DEFAULT profile the active power profile. User X logs on to the same computer. The active power profile is now read from user X’s user profile. User X logs off the computer. User X’s power profile remains the active power profile for the computer. Windows XP does not make the .DEFAULT power profile the active power profile. User Y logs on the computer. User Y’s power settings now become the active power profile. User Y’s power settings remain the active power profile after they log off the computer. We restart the computer and, once again, the active power profile is read from .DEFAULT.

Group Policy Preferences Power Options

Understanding how Windows XP manages the active power profile helps us better understand how Group Policy Power Option preference items manipulate Windows XP’s active power profile. Let’s start with computer startup. We’ve established that Windows XP reads power settings from the .DEFAULT profile into the active power profile. A Power Option preference item applying to a Windows XP computer does two things: it changes the power settings in the .DEFAULT profile and it makes those new settings the active power profile. A Power Option preference item applying to a user does two things: It changes the power settings in that user’s profile and it makes those new settings the active power profile. Remember there is only one active power profile—it’s the profile that was last made active.

Precedence

So predicting GPP Power Option precedence is trivial for computer startup and user logon. But background refresh can introduce some confusion. The computer starts up and receives GPP Power Item A. GPP Power Item A becomes the active power profile. User X logs on and receives GPP Power Item B. The active power scheme changes from A to B. Now, let’s presume that User X is a local administrator. This means User X can change the power settings, which changes the active power settings. So, User X changes the active power profile to power settings C. Now, a Group Policy background refresh occurs.

The background refresh changes the active power profile. And, as we previously covered, the last applied GPP Power item is the active power profile. When we last left our example computer, the active power profile was power settings C, which were created when the user changed their settings using the user interface. If the computer receives GPP Power Item A, and the user receives GPP Power Item B, then what is the resulting power profile? Power item B becomes the active power profile because it is the last power profile that is made active.

Let’s change the scenario. Let’s deploy GPP Power Item A to the computer and not deploy anything to the user because we want to apply a single power profile that affects all the users of the computer. Makes sense right? No, not in this case. The computer starts up and applies GPP Power Item A to .DEFAULT and makes GPP Power Item A the active power profile. User X logs on, and does not have a GPP Power item applied. The user loads their power profile from their user profile, and it becomes the active power profile. The power profile does not change until the user changes it (the need to be a local administrator) or during Group Policy refresh when the computer reapplies the GPP Power item; thus becoming the active power profile. You need combine Group Policy loopback processing (in replace mode) with GPP Power items to create one single GPP Power item that applies to all users of a computer.

Summary

I could easily add another five pages to cover all the different combinations of GPP Power items between computer and user settings. However, the main important thing to remember is there is only one active power profile for the entire computer running Windows XP. And, the active power profile is the power profile that was made active on the computer, regardless if it was done in the context of the user or computer.

— Mike Stephens

It’s time we wrap up our discussion on managing power using Group Policy. The previous blog posts discussed managing power on Windows Vista (and Windows Server 2008). Today, I’ll cover how we can achieve the equivalent for Windows XP.

The key to managing power on Windows XP is Group Policy preferences. The Group Policy Management Console (GPMC) included with Windows Server 2008 and (soon to be released) Remote Server Administration Tools contains the management portion of portion of preferences. Next, you need preference client side extensions that allow Windows XP to process Group Policy objects that contain preference configuration data. Group Policy preferences client side extensions are available from Microsoft for Windows Vista, Windows Server 2003, and Windows XP.

Preferences provide two preference items you can use to configure power on Windows XP (or Windows Server 2003 and Windows Server 2003 R2). The first of these items is the Power Option item. Figure 1 shows you the properties on a Power Option preference item. This is one of the great features with preferences—the configuration screen closely resembles the screen you actually use on the operating system.The Power Option preference item gives you the ability to configure hibernation, prompting for password when the computer resumes. Also, you can configure the Power button action when you close the lid of the computer (laptop), press the power button, or press the sleep button.

One of the cool things about preferences is you have control over which settings you want to configure and ones that you do not. Figure 1 shows each setting in the preference item underlined with a single green line. This means the setting in the item is enabled and the setting applies as configured. Using Figure 1 as an example, the Always show icon on the taskbar is enabled but, the checkbox is not selected. During Group Policy processing, this preference item configures Always show icon on the taskbar, Prompt for password when computer resumes from standby, and Enable Hibernate as off. This result is because the setting in the item was enabled (green underline) and the checkbox is cleared (off). This is a very powerful feature because it allows you full control over the setting you want to configure and the setting that you do not. Let’s look at another example.The above image shows another configured Power Options preference item. In this example, Always show icon on the taskbar has a red dashed underline, which means the setting is disabled. This means when Group Policy applies this preference item, Prompt for password when computer resumes from standby and Enable hibernation are enabled and, Always show icon on the taskbar is ignored. You enable and disable a setting by using the function keys on the keyboard.

• F5 enables all the settings in a preference item
• F6 enables the currently selected setting in a preference item
• F7 disables the currently selected setting in a preference item
• F8 disables all the setting in a preference item

NOTE:
Preference items are not policy settings, which means they are not enforced—just applied. Users with the proper privileges may have the ability to change the preference setting to another selection. However, preference item settings return on the next Group Policy refresh, unless configured otherwise.

The other power preference item is Power Scheme. The Power Scheme preference item allows you to create, modify, and delete power schemes. This allows you to configure a Windows XP computer to use one of the pre-existing power schemes or modify the settings included in one of the pre-existing power schemes or, just you create your own—it is your choice. Each power scheme has settings for two options: Plugged in or Running on batteries. From there, you define the time out settings for turning off monitors, hard disks, system standby and system hibernate. The Power Scheme preference item has the same enable/disable feature as the Power Option preference item and behaves in the same fashion.

The one difference with the Power Schemes preference item is the Action field. The action field determines the action Group Policy processing applies to the specific preference item. Configuring a Power Scheme preference item to Create; does just that—it creates a new power scheme. However, if, on the computer applying the preference item, a power scheme with the same name exists, the preference item does nothing. Delete and Update do just what they describe—delete and update. However, Update does provide additional functionality other than updating an existing power scheme with new settings. If you configure your Power Scheme preference item to update a power scheme that does not exist on the applying computer, then a new power scheme is created with that name. Lastly, configuring the preference item with Replace has similar results to using Update. When using Update, the Power Scheme preference item only updates the enabled settings within the preference item on the existing named power scheme—leaving all other settings as they are. Replace, however; actually deletes the named power scheme from the computer and then creates a new power scheme based on the settings configured in the Power Scheme preference item.

Other things to remember with power management preference items:

• You can configure power management preference items in both computer and user configurations. Understand, user configuration apply after computer configuration. This results in the user settings replacing the current power settings, which could have been from another preference item.
• Local Administrators are Administrators. This means they can change their power configuration. Standard users cannot.
• When Group Policy applies power management preference items; those items become the current power management scheme—even after the user logs off.
• Power management preferences item support background refresh—your settings can change.

That wraps up Managing Power with Group Policy. Three blog entries, six categories, 34 policy settings, and two preference items later, it should be easy to see how combining these Group Policy features could save your company significant resources. It may be a good time to review how you could implement some of these features and savings you may gain.

Managing Power with Group Policy: Part 1 of 3
Managing Power with Group Policy: Part 2 of 3
Managing Power with Group Policy: Part 3 of 3

-Mike Stephens