CSPV - Tips

Tip 21: Windows 2000 and above to break the 26 drive letter limitation

Windows 2000 NTFS offers functionality called "junction points" with which you can surpass the 26 drive letter limitation using directory symbolic links. With this a directory serves as a symbolic link to another directory on the computer. These symbolic links, or reparse points, allow any Windows 2000 folder to be mounted at any point. You can use MountVol.exe to mount any number of volumes. Reparse points are the underlying mechanism on which NTFS junctions are based, and they are also used by Windows 2000’s Remote Storage Service. Without duplicating files (and thus wasting valuable disk space), you could have a folder and its directory tree mounted in one or more other locations.

The junction point tools are:

LinkDd.exe which is used to create/delete junction folders onto Windows 2000 NTFS and is found in the Windows 2000 Resource Kit.
LinkD grafts (links) the target name directly into the name space at Source, so that Source subsequently acts as a name space junction. The Source directory must reside on a disk formatted with NTFS in Windows 2000. The destination (the target of the link) can be any valid directory name or device name or valid object name in Windows 2000.

MountVol.exe which mounts/unmounts the root folder of a local volume onto a Windows 2000 version of NTFS folder, that is, mounts/unmounts the volume.
Mountvol.exe is in the I386 of the Windows 2000 CD.

Delrp.exe deletes reparse points, which are the entities underlying junction points and is part of the Windows 2000 Resource Kit.
Delrp.exe seems like LinkD.exe but has particular value for developers whereas LinkD is an administrators utility.

System Internals have written a freeware junction utility called Junction, which duplicates the capability of LinkD to create reparse points while at the same time allowing one to browse and see whether a folder is a folder or a symbolic link, that is a reparse junction. Periodically check System Internals, because they do a wonderful job supplying valuable freeware and commercial utilities of great value to Windows NT/2000 administrators.

Obviously the underlying technology of reparse points is very powerful and gives Windows 2000 tremendous capabilities. These junctions allow I/O redirection, name space reloading and other capabilities. This technology built into Windows 2000 provides hierarchical storage management. Unused files could be archived to tape or removable drives. When you subsequently try to access an archived file or folder, the reparse point could mount the archival media for retrieval. This is just one of the capabilities inherent in the technology.