When you manage desktop and laptop systems, you'll often want to perform routine maintenance tasks on a periodic or recurring basis. To do this, you can use the Task Scheduler service to schedule one-time or recurring tasks to run automatically. You automate tasks by running command-shell scripts, Windows Script Host (WSH) scripts, or applications that execute the necessary commands for you. Unlike earlier releases of Windows, Windows Vista includes an extensive library of preconfigured tasks. These tasks handle everything from uninstalling a Bluetooth device to defragmenting disks to performing Windows Defender scans.
Windows Vista provides several tools for scheduling tasks, including the Scheduled Task Wizard and the Schtasks command-line tool. Both can be used for scheduling tasks on local and remote systems. The Scheduled Task Wizard provides a point-and-click interface to task assignment, and Schtasks is its command-line counterpart.
Both scheduling tools use the Task Scheduler service to monitor the system clock and run tasks at specified times. The Task Scheduler service logs on as the LocalSystem account by default. This account usually doesn't have adequate permissions to perform administrative tasks. To overcome this problem, each task can be set to run as a specific user, and you set the user name and password to use when you create the task. Be sure to use an account that has adequate user privileges and access rights to run the tasks that you want to schedule.
The focus of this section is on the Scheduled Task Wizard. This is the primary tool you'll use to schedule tasks on Windows Vista systems. To learn more about Schtasks, type schtasks /? at the command prompt or refer to Chapter 4, "Scheduling Tasks to Run Automatically," in the Microsoft Windows Command-Line Pocket Consultant (Microsoft Press, 2004).
Windows Vista has two general types of scheduled tasks:
Standard tasks Used to automate routine tasks and perform housekeeping. These tasks are visible to users and can be modified if necessary.
Hidden tasks Used to automate special system tasks. These tasks are hidden from users by default and should not be modified in most cases. Some hidden tasks are created and managed through a related program, such as Windows Defender.
In Windows Vista, the creation and management of tasks is much more sophisticated than ever before. Every task can be configured to:
Run only when a user is logged on, or to run regardless of whether a user is logged on
Run with standard user privileges, or to run with the highest privileges required (including administrator privileges)
Because tasks created on Windows Vista are not compatible with earlier releases of Windows, you cannot copy a Windows Vista task to a computer running an earlier release of Windows and expect the task to run. However, when creating the task, you can specify that it should be created so that it is compatible with earlier releases of Windows. This would then allow you to copy the task to computers running earlier releases of Windows.
Tasks can have many properties associated with them, including:
Triggers Triggers specify the circumstances under which a task begins and ends. You can begin a task based on a schedule, user logon, computer startup, or processor idling. You can also begin a task based on events, a user connecting or disconnecting from the Terminal Server session, or a user locking or unlocking a workstation. Tasks with event-based triggers can be the most powerful, because they allow you to provide automated ways to handle errors and warnings.
Actions Actions define the action a task performs when it is triggered. This allows a task to start programs, send e-mail messages, and display messages.
Conditions Conditions help to qualify the conditions under which a task is started or stopped once it has been triggered. You can use conditions to wake the computer to run a task and to start the computer only if a specific network connection is available. You can use conditions to start, stop, and restart a task based on the processor idle time. For example, you might want to start a task only if the computer has been idle for at least 10 minutes, stop the task if the computer is no longer idle, and then restart the task again if the computer becomes idle once more. You can also use conditions to specify a task should only start if the computer is on alternating current (AC) power and stop if the computer switches to battery power.
The current tasks configured on a system are accessible through the Task Scheduler node in Computer Management. You can view and manage the scheduled tasks configured on a computer by completing the following steps:
Open Computer Management. You are connected to the local computer by default. If you want to view logs on a remote computer, right-click the Computer Management entry in the console tree (left pane) and then select Connect To Another Computer. Then, in the Select Computer dialog box, enter the name of the computer that you want to access and then click OK.
Expand the Task Scheduler node and then expand the Task Scheduler Library node and related subnodes as necessary to view the configured schedule tasks.
Select a task to view its properties using the tabs provided, as shown in Figure 1. If you want to manage the task, right-click the task and then:
q Delete a task by selecting Delete.
q Disable a task by clicking Disable.
q Edit the task's properties by clicking Properties, making the appropriate changes in the Properties dialog box, and then clicking OK.
q Export a task to a file that can be imported on another computer by selecting Export. After you export the task, use Computer Management to connect to the other computer, right-click the Task Scheduler Library node, and then select Import Task. You can then use the Open dialog box to locate and open the task in the other computer.
q Run the task by clicking Run.
q If the task is running, stop it by clicking End.
Figure 1: View and manage scheduled tasks.
Although you can modify and delete user-created tasks, most tasks created by the operating system cannot be configured or deleted. You can view hidden tasks by clicking View and then selecting Show Hidden Tasks.
You can view the scheduled tasks currently running on a computer by completing the following steps:
Open Computer Management. You are connected to the local computer by default. If you want to view logs on a remote computer, right-click the Computer Management entry in the console tree (left pane) and then select Connect To Another Computer. In the Select Computer dialog box, enter the name of the computer that you want to access and then click OK.
Right-click the Task Scheduler node and then select Display All Running Tasks.
To create a task using the Scheduled Task Wizard, follow these steps:
Select and then right-click the Task Scheduler node and then select Create Task. This starts the Create Task Wizard.
On the General tab, type the name of the task and then set security options for running the task.
q If the task should run under a user other than the current user, click Change User Or Group. Use the Select Users Or Groups dialog box to select the user or group under which the task should run and then provide the appropriate credentials when prompted later.
q Set other run options as necessary using the options provided. By default, tasks only run when a user is logged on. If you want to run the task regardless of whether a user is logged on, select Run Whether User Is Logged On Or Not. You can also elect to run with highest privileges and configure the task for earlier releases of Windows.
q On the Triggers tab, create and manage triggers using the options provided. To create a trigger, click New, use the options provided to configure the trigger, and then click OK.
q On the Actions tab, create and manage actions using the options provided. To create an action, click New, use the options provided to configure the action, and then click OK.
q On the Conditions tab, specify any limiting conditions for starting or stopping the task.
q On the Settings tab, choose any additional optional settings for the task.
q Click OK to create the task.
When you configure tasks to run on a computer, you can encounter several types of problems. Some tasks won't run when they are supposed to. Others will start and won't stop. To determine the status of a task, select the task in the Task Scheduler and note the status, last run time, and last run result. If a task has a status of Queued, it is waiting to run at a scheduled time. If a task has a status of Ready, it is ready to run on its next run time. If a task should be running automatically but has a Last Run Time of Never, you'll need to check the task's properties to determine why it isn't running. If the Last Run Result is an error, you'll need to resolve the referenced problem so the task can run normally. Check a task's properties by clicking its entry in the Task Scheduler. The History tab provides detailed information on the task, from creation to its last run time. Use the history information to help you resolve problems with the task.
A task that is listed as Running might not in fact be running but instead might be a hung process. You can check for hung processes using Last Run Time, which tells you when the task was started. If a task has been running for more than a day, there is usually a problem. A script might be waiting for input, it might have problems reading or writing files, or it might simply be a runaway task that needs to be stopped. To stop the task, right-click it in the Task Scheduler and then select End.
