When it comes to managing disk partitions, things haven't changed that much since the days of DOS. Most partitions have a letter, and you're expected to know which letter goes to which partition. If you add a new device of any kind, it usually gets the next available letter. That often isn't the best solution. For example, wouldn't it be nice to add more storage but make it look like part of your existing drive space? Windows Disk Manager can help you do that, at least on Windows 2000/XP.

Drives Lacking Letters

Starting with the version of the NTFS file system that was released with Windows 2000, you can now access drives without assigning a drive letter to them. This applies not only to hard disk drives permanently installed in your system but to any type of storage device, such as CDs, DVDs, USB flash drives, or FireWire external drives. The NTFS features that let you do this are called reparse points. In the most general case, a reparse point will even let you connect one folder to another folder somewhere else on the drive, but I'll leave that advanced topic for a future column. For now, we're interested in a particular kind of reparse point called a "mount point."

Using mount points, you can tell Windows to treat an empty folder as the spot to attach another drive. The drive can either be permanently installed or a removable. The same drive can be mounted in multiple folders and even have a drive letter attached to it as well. That can become confusing though, so the most common situation is that you assign just one drive letter or folder to each drive. Once you have mounted a drive on a folder and are happy with its location, you'll usually want to remove the letter to avoid confusion.

Manage Mount Points

To create mount points, you run the Windows Disk Manager utility. To get to the utility, right-click My Computer, select Manage, and then click the Disk Management item. In the right-hand pane, you should see a list of all the physical disk drives on your system and a map of which partitions are on which drives. Note that all your drives are shown here, including CD/DVD drives and any removable storage that is currently plugged into the system through a USB or Firewire connection.

To add or change mount points, right-click the partition that you want to change and select Change Drive Letters And Paths. In most cases you will see a drive letter there already. Next, click Add and enter the full path to the empty folder you want to use. Don't change or remove the drive letter of the boot partition (usually the C: drive), but any of the other drives shown in Disk Manager are usually fair game. You can either leave the drive letter assignment or remove it. If you have already used a drive while it had its original drive letter assignment, there may be programs or other parts of the system that have "remembered" that drive letter. You can always add the drive letter back if you have problems down the road.

Note that the folder you use for a mount point must be completely empty. If the folder isn't empty, the OK button on the Change Drive Letters And Paths dialog box won't be enabled. One cause of this is if you have the Show Common Tasks In Folders enabled. (Click Tools and Folder Options in Explorer.) That can create a hidden file named Desktop.ini in the folder that will prevent the folder from being used as a mount point. You can manually delete the file by clicking Tools, Folder Options, and Advanced and then selecting Show Hidden Files And Folders; only then can you use the folder as a mount point.

Folders As Holders

Here's a nifty way to use mount points to keep track of USB flash keys. These handy little gizmos are so tiny that I often forget to take them out before I leave the PC, especially on systems that only have rear USB ports. Mount points give you a visual indicator of whether your USB flash key is plugged into the system and ready to use. If you have multiple flash keys, you can create a different folder mount point for each one, so it's easy to tell which key you plugged into the system.

First, create an empty folder on your Desktop or, if you prefer, in a folder that you frequently have open, such as MY DOCUMENTS. If you have multiple USB keys or other removable storage devices that you plug into the system, name the folder after the specific device that you are setting up this time. Then plug in that device and go to Disk Management to set up the folder as described above.

As soon as you've set up the mount point folder, you'll see the standard yellow folder icon change to a gray disk drive icon. That's your indication that the device is currently plugged into the system. Unplug the device, and the folder will change back to its standard icon. Each time you plug that specific device into the system, Windows will change the icon, and you can access its files through the folder. Now you can tell with a quick glance at your Desktop what stuff you currently have plugged into the system!

Notice that Windows is pretty smart about knowing which device is which. If you have multiple USB ports, it will recognize the device and use the proper folder no matter which port you use. How can Windows know the difference between two USB flash memory keys and decide which folder it should use as the mount point? It's not deeply magical, as magic things go. Each time you format a drive, it gets a unique number known as a volume ID. When you plug the drive into your system, Windows looks at the volume ID and decides which mount point it should use.

Mysteries & Wonders

Whenever you plug in removable storage, such as a USB external drive, Windows tries to be "helpful" by scanning the drive to determine what's on it and guessing what you might want to do with it. For example, if the drive contains music, it might open up Windows Media Player. If it contains pictures, it could show you thumbnail views of the files. If you frequently plug in drives, the best way to describe this feature is "annoying." On a slow link, such as USB 1.1, it can take Windows a long time to figure out what you might want, and it's often wrong. Fortunately, you can disable this feature. Get a copy of TweakUI (www.microsoft.com/windowsxp/downloads/powertoys/default.mspx) and go to the settings for My Computer, AutoPlay, and Types. Clear the checkbox for "Enable AutoPlay For Removable Drives."

One thing that I have wanted to do, but haven't figured out, is how to change the icons displayed when a mount point is empty or in use. It's possible to customize folder icons on normal folders, but it requires a Desktop.ini file in the folder, and that's a no-no for mount point folders as I mentioned above. Windows doesn't seem to pay attention to a Desktop.ini file in the root of the drive, even when it specifies another icon. So for now at least, you'll have to make do with the yellow folder and gray drive icons. If any of you figure out how to do this, please drop me a line.

by Dave Methvin