Windows 7 : Disk Management (part 1) - Assigning Drive Letters and Joining Volumes

Now that we’ve covered the essentials of basic and dynamic disks, and tips for optimizing and organizing storage, this section focuses on managing your computer’s disks.

The Disk Management utility (shown in Figure 1) is responsible for the creation, deletion, alteration, and maintenance of storage volumes in a system. This tool is located within the Computer Management interface of Administrative Tools (accessed through Start, Control Panel, System and Security, Administrative Tools, Computer Management, Disk Management). It is protected by User Account Control. Another access method is right-clicking Computer and choosing Manage. Using the Disk Management utility, you also can assign the drive letters used by your DVD and hard disk drives.

Figure 1. The Disk Management tool is part of Computer Management.

This single interface lets you manage both local and remote computers using the various administration utilities shown in the left pane. Using this interface, I’ll show you shortly how to perform different procedures on your existing and new hard disks. The process is quite simple for most of the operations because you will be presented with a wizard to complete them.

Most operations on disks can be performed by right-clicking the disk or volume you want to affect. As usual, you are presented with a context-sensitive menu from which you can perform any actions relating to the volume or disk you click. From the graphical layout in the Disk Management utility, you can also see what is going on with your disks at any given time. As always, you can select the Help option from within any right-click context menu or the menu bar along the top of the window to get an explanation of the operations available to you.

1. Assigning Drive Letters and Joining Volumes

Windows automatically assigns letters to the drives. However, this assignment might not suit your system; for example, you might have already mapped a network drive to the same letter that Windows assigns to a new drive.

Using Disk Management, you can easily assign logical drive letters to your hard disks and removable drives such as DVD or Iomega REV. You can’t change the drive letter of your boot drive (usually the C: drive), but you can change any of the others.

To change the letter, right-click the disk volume or drive in the bottom-right pane of Disk Management, and select Change Drive Letter and Paths. A dialog box appears, listing the current drive letter assignment. Click Change. Under Assign the Following Drive Letter, choose the desired new letter. Click OK and confirm that you really do want to make the change.

In addition to or instead of assigning a drive letter to a disk drive or partition, you can “graft” the disk volume onto another. Windows lets you specify a folder that will become the mount point for the new drive. For example, let’s assume you create a folder named C:\TEMP, and you want it to have a lot of drive space. You could install a new hard drive and, instead of assigning it a drive letter, tell Windows to access it through C:\TEMP. Your C:\TEMP files and subfolders are then stored on the alternate drive.

Grafting Versus Dynamic Disks

Assigning mount points is different from what happens when you aggregate dynamic disks into one large volume. Although dynamic disks and regular (basic) disks both support the use of mount points, dynamic disks can create one large, apparently contiguous disk space. Mount points graft subsequently added drives at a folder, similar to grafting two trees by tying together a branch from each tree. Figure 2 illustrates the differences between the two approaches.

In Figure 3, I’ve grafted a hard disk containing digital photos (J:) into the mount point on drive C:\Users\Marcus_S\Pictures\More Pix.

Figure 3. Assigning a partition or volume to a folder rather than a drive letter joins the volume to an existing volume. The contents of the added volume appear as subdirectories of the mount point folder.

Even if you have several hard drives and DVD drives, you can graft them all together onto your C: drive, making it appear as one big file system. It’s a great management concept: You can add space to your file system by attaching new disk volumes directly into the original folder structure. (UNIX users are probably smirking at this point because the UNIX OS has worked this way since it was written in the 1970s.)

If you mount a drive and assign it a drive letter, you can access it through both pathways.

To graft a disk volume to an existing file system, follow these steps:

You can assign a given drive or volume to only one drive letter but to an arbitrary number of paths. (It’s a little strange to see the same files appear in several different places, so we recommend that you not go nuts with this feature.)

By the way, this “grafting” technique works with both basic and dynamic NTFS disks. Only Windows dynamic disks can be “grown” by changing their partition size on the fly. If you use a basic-formatted disk, as most users do, the grafting trick is a good one to know.