Talk:NTFS junction point

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Junction points seem to be a hidden feature of NTFS 5.0 :)

Please stop the FUD. They're documented in the standard Microsoft fashion. In short, that means it's not on Google (or MSDN), but in (for example) the relevant SDKs, one of them being the Platform SDK, as someone's already pointed out. I'll agree it's an underused and underdocumented feature though. --Ultomten (talk) 11:24, 26 November 2007 (UTC)

Undocumented by Microsoft as far as I know, and little documentation on the net otherwise, these can be used almost the same as symbolic links.

However since they are so underdocumented, it's hard to tell what happens when you perform file operations on them, eg copy, move, delete, etc... and whether the effect changes if these operations are instigated from explorer, console, programs, etc or different OS's (I believe WinXP uses NTFS 5.1, whereas Win2000 uses NTFS 5.0) - there could be hidden dangers which might risk your data.

That's the reason for the observed effects section, so please expand it if you get a chance to test things out.

Zarius 22:47, 23 Feb 2004 (UTC)


They are documented in Platform SDK, AFAIK. And NT Resource kit contained both the ln tool and the documentation for symlinks/hardlinks. --tyomitch 14:03, 10 September 2005 (UTC)

Regarding "Microsoft uses them internally to maintain backward naming convention compatibility for user's profile's among other things". This seems to be pure guesswork. On my Vista, NTFS Junction Points were created during installation to map folders like "Documents and Settings" to their new counterparts. However, they don't actually work, due to errors in the link targets, so I'm not sure what's up. This might be because I did an "upgrade" (from XP) and not a "regular installation", so I won't change anything on the page.

--Ultomten (talk) 11:24, 26 November 2007 (UTC)

Regarding the layout of the Observed effects section, I think it best laid out like this:

  • Win XP Pro -- Pro at the moment, since this is the OS I currently use & I can't test if XP Home has any different effects - given the data risk, I thought I'd play it safe and assume difference until proven otherwise)
    • deletion via blah has this effect
    • effect
    • etc
  • Win 2000
    • deletion via blah has this effect
    • move via blah has the same effect as Win XP Pro above
    • etc

This does involve some duplication of information, but makes it easier for someone to check out the effects on the OS they are currently running.

Zarius 22:47, 23 Feb 2004 (UTC)

Oops! :) On an earlier version of the page I stated that deleting via explorer was safe... it's not. The junction had just been transferred to the recycle bin, not actually deleted and therefore the files were still safe - until you empty the recycle bin :) Then *poof* there go all the files in the targeted directory :)

Zarius 23:36, 24 Feb 2004 (UTC)

Hmm... it seems a bit much to refer to them as junction points all the time (not to mention the typing :)) - but what's a better way to refer to them? I've been using both junction and JP's, leaning towards JP's.

Zarius 23:36, 24 Feb 2004 (UTC)

Here's some more info that might be relevant: (cut from Microsofts KB article Q262797)

The following technologies use reparse points:
  • Directory Junctions is a technology for a folder to be grafted into another folder on the same local computer. Directory Junctions work when they are mounted on the same volume. If a Directory Junction is mounted such that the target folder and host folder are on different Physical Disk resources, the resources must be in the same cluster group. The Physical Disk resource that contains the host folder should be dependent on the Physical Disk resource that contains the target folder. If the drive that contains the target folder does not come online, the drive that contains the host folder does not start.

Zarius 02:36, 25 Feb 2004 (UTC)

[edit] Vista does have the RMDIR command

Removed as this is incorrect:

  • Windows Vista no longer uses rmdir, but still has rd.