AW: [Mono-list] Directory Symbolic link?

Richard Matthias
Tue, 10 Feb 2004 16:07:52 -0000

The data in the file tells ntfs to call an installable filter. That
filter can then return data from somewhere else. The feature is used for
lots of things like the Encrypting File System, the Removable Storage
Management (that allows files to be archived while still appearing in
the file system). It's what allows you to mount devices (both partitions
and network shares) in folders of other drives rather than assigning a
drive letter for each, a la unix. Most interestingly it is used by
Exchange Server 2000 onwards to expose the contents of its database as a
directory tree with items appearing as files.

If you want a parallel, think about the Linux loopback device. Although
NTFS installable filters run in kernel space AFAIK, they can communicate
with user space programs like Exchange Server to provide data. Technical
details are in the DDK, but there's a high level description of what's
possible in the following page:

>-----Original Message-----
>[] On Behalf Of Jochen Wezel
>Sent: 10 February 2004 15:16
>To: egonia;
>Subject: AW: AW: [Mono-list] Directory Symbolic link?
>Hi Eric,
>You've trapped into a dark, seldom seen world. There is no=20
>great documentation or anything else. My knowledge is from the=20
>study of the NTFS file system and some tools which are=20
>creating such symbolic links. A reparse point is a small=20
>script or some data inside a file system entry which says:=20
>"no, I'm not your file you're asking for, but I know where to=20
>get it from"
>-----Urspr=FCngliche Nachricht-----
>Von: egonia []=20
>Gesendet: Dienstag, 10. Februar 2004 15:12
>An: Jochen Wezel
>Cc: Gonia Eric - egonia; Alejandro Mery;
>Betreff: Re: AW: [Mono-list] Directory Symbolic link?
>What exactly is a ReparsePoint?
>This is what the .Net SDK has to say about it:
>"The file contains a reparse point, which is a block of=20
>user-defined data associated with a file or a directory."
>I guess this is probably my own ignorance, but would someone=20
>kindly explain reparse points to me?
>I could not find anything with google on the matter.
> Jochen Wezel <>:
>> Maybe, your question could be answered with the search for reparse
>> points:
>> System.IO.DirectoryInfo a;
>> bool IsSymbolicLink =3D a.Attributes.ReparsePoint;
>> Jochen
>Mono-list maillist  -