Like most administrators, whenever I needed to solve a hardware problem in Windows NT, I wished I could use the Windows 9x Device Manager. This tool makes viewing and configuring device settings a snap and also simplifies troubleshooting hardware problems that result from settings conflicts or incorrect drivers.

I was delighted to find Device Manager in Windows 2000. If you have nothing but Plug and Play (PnP) devices throughout your Win2K system, you won't need to configure or troubleshoot hardware and you don't need to read this article. However, I suspect I could fit around my dining room table all the enterprise systems administrators to whom that statement applies. Using Device Manager, you can make configuration changes, install and uninstall devices, and generally resolve problems without much trouble.

Accessing Device Manager


Device Manager is a Microsoft Management Console (MMC) snap-in. To open Device Manager, you can use one of the following methods:

  • Right-click My Computer and choose Manage to open the local MMC Computer Management console. Select the Device Manager object under Computer Management, System Tools to display Device Manager in the console's right pane, as Figure 1, page 130, shows.
  • Right-click My Computer, and choose Properties to open the System Properties dialog box. Move to the Hardware tab, and click Device Manager to open Device Manager as a standalone console, which Figure 2, page 130, shows.
  • Type
devmgmt.msc

from the Run command or the command prompt to open Device Manager as a standalone console.

Viewing Devices


By default, Device Manager displays devices alphabetically by type (i.e., class). Expand each type listing to reveal the devices in that type. Usually, no classes are expanded when you open Device Manager. However, if a device has a problem, its class is expanded and the device's listing displays a yellow exclamation point.

To examine or manipulate a device, expand its class and double-click the device listing to open its Properties dialog box. The dialog box always includes a General tab (which Figure 3, page 130, shows) that reports the device's current status, and a Driver tab, on which you can view detailed information about the device's driver as well as update the driver. Most devices also provide a Resources tab, which shows the resources that the device uses.

By default, Device Manager hides several devices; to view them, choose View, Show hidden devices from the console menu. On most systems, this action results in the display of a Non-Plug and Play Drivers device class, which expands to a list of drivers that support system services. Other drivers might also appear, depending on the types of installed devices and drivers on the computer. For example, by default, expanding the Network adapters class shows only the physical NIC or NICs, but when you expose hidden devices you'll also see such drivers as the WAN miniport drivers for IP, PPTP, and other protocols.

You can rearrange the order in which Device Manager displays devices. From the View menu, choose one of the following options:

  • Devices by connection sorts the list according to the device's connection (e.g., COM2, system board).
  • Resources by type sorts the list according to the resources attached to each type of
    device.
  • Resources by connection sorts the list according to the resources that each connection type uses.

These views are handy for figuring out conflict problems. For example, either of the last two options provides an easy way to check IRQ assignments. Simply choose one of those views and expand the Interrupt request (IRQ) listing, as Figure 4 shows.

Configuring Devices


You can also use Device Manager to configure devices—for example, to change resource settings or to change or update drivers. (Not all devices offer a full range of configuration options; some devices are locked in to their settings.) And you can use Device Manager to enable or disable a device, which often provides a temporary cure for a resource conflict. (Again, not all devices offer these options—hard disks are a prime example.)

Changing resources. To change resources for a device, go to the Resources tab on the device's Properties dialog box. Select the resource you want to modify, clear the Use automatic settings check box, and click Change Setting. An appropriate dialog box opens. For example, when you select Interrupt Request, the Edit Interrupt Request dialog box, which Figure 5 shows, appears. Use the up and down arrows to the right of the Value text box to select a new setting. (You can manually enter a new setting, but the Value box has an advantage—it offers only valid choices.) As you select settings, the dialog box displays messages about conflicts, either stating that no conflicts exist or warning you that the setting conflicts with another device's setting.

Updating drivers. To update device drivers, go to the Driver tab and click Update Driver. The Upgrade Device Driver Wizard opens and walks you through the process. You can install drivers from a CD-ROM, 3.5" disk, local file, or network share point.

Disabling devices. You can disable a device, thus freeing the resources the device had been using. You can use this feature to troubleshoot resource-allocation problems; disabling a device lets you determine whether another device (which might have a resource conflict with the disabled device) works properly. Another common practice is to disable a device for a specific hardware profile. Laptop computers are the usual targets for hardware profiles, which let users choose to boot to a docking station. (Hardware profiles, which you create and configure from the System Properties dialog box's Hardware tab, are only necessary for non-PnP devices.)

Disabling a device doesn't remove it from Device Manager or remove the device's settings from the registry. The process simply makes the device unavailable and frees the resources it was using. After you disable a device, a red X appears atop the device's icon in Device Manager. To reenable the device, open the device's Properties dialog box and click Enable Device.

Uninstalling Devices


You should always uninstall a non-PnP device from Device Manager before you remove the device from the computer. (Win2K's Plug and Play feature doesn't enumerate PnP devices that you remove from a computer, so as far as Device Manager is concerned, the device simply disappears and no longer exists.)

To uninstall a legacy device, select the device and choose Uninstall from Device Manager's Action menu (or right-click the device listing and choose Uninstall from the shortcut menu). You must confirm your action.

In theory, uninstalling removes the device from Device Manager and removes the device's settings from the registry. However, some registry entries don't go away after a device's uninstallation. These entries seem to do no harm, even when another device uses the resources that the uninstalled device abandons.

Searching for New PnP Devices


If you attach a PnP device to your computer while the computer is running, Win2K's Plug and Play feature doesn't automatically find the device because Plug and Play enumerates your system during OS startup. (You shouldn't attach these devices this way, but many of us ignore that rule when installing printers or modems.)

To force the computer to search for new PnP devices without rebooting, select Scan for hardware changes from Device Manager's Action menu. The OS should find your new device and display the standard New Hardware Found message. If the OS doesn't find the device, the device probably isn't PnP. In that case, you'll need to use the Control Panel Add/Remove Hardware applet to perform a manual installation.

Troubleshooting Devices


When a device listing displays a yellow exclamation point, the device has a problem. The device's Properties dialog box usually offers a rather vague and unhelpful message about the problem, an error code number, and a message encouraging you to click Troubleshooter to try to resolve the problem. Clicking that button opens a hardware troubleshooter, which asks questions and then makes suggestions (or asks additional questions) in response to your answer. I've heard a rumor that Troubleshooter can actually resolve a problem, but I've never had this experience. What I do have is the Microsoft article "Explanation of Error Codes Generated by Device Manager" (http://support.microsoft.com/support/kb/articles/q125/1/74.asp), which enumerates the error code numbers and frequently points me in the right direction. In my experience, this article is certainly more helpful than Troubleshooter.

Printing a Report


The Device Manager's View menu includes a Print option that you can use to generate a printed report of your computer's devices. The Print dialog box gives you several options:

  • System summary prints summary information about all the devices. (Many administrators print this information and store the printout so that after a major disaster, reconfiguring resources—especially for non-PnP devices—is quick and easy.)
  • Selected class or device prints information about the object you selected before you chose the Print option.
  • All devices and system summary prints more than most people ever want to know about every device on the system.

The Print dialog box also includes a Print to file option, which is good because these reports (especially the third choice) can be quite large and you might want to wait to send the print job until your printer is idle. However, the resulting file is specific to the selected printer (use the command copy filename.prn LPTx /b to send the file to the printer) and you can't view the file on screen. For such reasons, I install a generic text printer on every computer and specify File as the port. I can open the resulting searchable text file in any editor or word processor, then use the software's Print command to print the entire file or selected portions.

The Payoff


Device Manager provides an easy way to solve resource conflicts, manually override configuration settings, and change devices' behavior. Incidentally, you can use Device Manager remotely only in read-only mode, but this option still lets you access device information throughout the network without leaving your desk.