NTFS reparse point
An NTFS reparse point is a type of NTFS file system object. It is available with the NTFS v3.0 found in Windows 2000 or later versions. Reparse points provide a way to extend the NTFS filesystem. A reparse point contains a reparse tag and data that are interpreted by a filesystem filter identified by the tag. Microsoft includes several default tags including NTFS symbolic links, directory junction points and volume mount points. Also, reparse points are used as placeholders for files moved by Windows 2000's Hierarchical Storage System. They also can act as hard links, but aren't limited to point to files on the same volume: they can point to directories on any local volume.