Links and Shortcuts

Hard links, Junction Points, Mount Points, Symbolic links and Shortcuts are linking mechanisms used to refer to other files, directories, or volumes.† By necessity DiskFerret contains specific logic to handle these ďspecialĒ file system objects. †With the exception of shortcuts and hard links, all of these links have the reparse point set in the fileís attributes.

Shortcuts

A Shortcut is a file interpreted by the Windows shell or other apps that understand them as paths to a file or directory. A shortcutís file size is equal to the binary information it contains and is treated as ordinary files by the operating system and by programs that donít understand them.† Deleting a shortcut only deletes the shortcut file, not the shortcut target. †Shortcuts maintain references to their target even if the target is moved or renamed, but are useless if the target is deleted.† Shortcuts can point to partitions or volumes on other systems, and are compatible with all windows systems.†

 

DiskFerret handles shortcuts in much the same way as Windows Explorer.† The size of a shortcut is the size of the binary information that it contains, not the size of the target.† Shortcuts to folders are not followed in DiskFerret scans as this would skew disk utilization results.† It the target of the shortcut is a file, opening (double click or context menu Open) the shortcut launches the application associated with the target file.† If the target is a directory, DiskFerret opens and scans the target folder.†

Junction Points

A Junction Point (or directory hard link) is a type of hard link that acts like a representation of a directory, a partition or another volume on the same system.† Junction points are interpreted at the operating system level and are transparent to most software programs.† In Windows, junction points display the same size as the target without duplicating the target (they donít use any space).† Deleting a junction point does not remove the target, and if the target is deleted, its contents are still available through the junction point.† Changing the junction point contents changes the targetís contents. Junction points are compatible with Windows 2000 and above.

 

DiskFerret does not follow junction points when it scans a disk or folder as this would skew disk size/utilization results.† Unlike Windows Explorer, which displays junction point contents as if the contents were children, opening a junction point by double clicking or using the Open context menu item in DiskFerret opens and scans the target of the junction point.† DiskFerret always displays the size as zero.

Symbolic Links

A Symbolic link (or soft link) is a file similar to a shortcut in that it points to a filename or directory name, but itís handled at the system level rather than at the application level.† In Windows, symbolic links to folders, volumes or network paths display the same size as the target without duplicating the target (they donít use any space).† Windows displays a size of zero for symbolic links to files.† Deleting the Symbolic link does not remove the target and if the target is moved, renamed, or deleted, the link points to a non-existing file or directory.† Symbolic links, unlike junction points, can point to a target representing a folder or volume on the same system, but can also point to remote network paths.† Symbolic links are compatible with Windows Vista and above.

 

DiskFerret does not follow symbolic links when it scans a disk or folder as this would skew disk size/utilization results.† Unlike Windows Explorer, which displays symbolic links contents as if the contents were children, opening a symbolic link by double clicking or using the Open context menu item in DiskFerret opens and scans the target of the junction point.† (If the symbolic linkís target is a file DiskFerret opens the file with its associated application.) †DiskFerret always displays a size of zero for symbolic links.

Hard Links

Hard links are directory entries that associate a file name with file data in the file system.† File data in the same volume may be referenced by more than one name which causes an aliasing effect.† For example, if the file is opened by one of its names and changes are made to its content, those changes will also be visible when the file is opened by an alternative name.† Hard links have the same size as the target without duplicating it (they donít use any space) and are interpreted at the operating system level.† Deleting a hard link does not remove the target file and if the target is deleted, its contents are still available through the hard link.† Changing the hard link contents changes the targetís contents.† Hard links must reside on the same partition as the target file.† Hard links are compatible with Windows 2000 and above.

 

Because of the overhead of resolving multiple file name references to the same data on a volume, DiskFerret treats each hard link as a separate file.† In the context of each directory path, DiskFerret displays the appropriate disk space occupied by the files in the path, but when multiple hard links to the same file exist in the same tree path the disk space is skewed because the file size is included in results each time that it is encountered.

Mount Points

Volume Mount Points are specialized NTFS file system objects which are used to mount and provide an entry point to other volumes. Mount points can be created in a directory on an NTFS file system, which gives a reference to the root directory of the mounted volume. In fact, any empty directory can be converted to a mount point. The mounted volume is not limited to the NTFS file system but can be formatted with any file system supported by Microsoft Windows. Volume Mount Points are supported from NTFS 5.0, which was introduced with Windows 2000.[1]

 

DiskFerret does not follow mount points when it scans a disk or folder as this would skew disk size/utilization results.† Unlike Windows Explorer, which displays mount point contents as if the contents were children, opening a mount point by double clicking or using the Open context menu item in DiskFerret opens and scans the target of the mount point.† DiskFerret always displays a size of zero for mount points.

 

 

 

References

1.     Wikipedia