hard link concept

NTFSD
1

hi all,
In my project, I want to link from one file to another for
this I use hard link concept and it works well on NTFS file system but
it will not work on FAT32 can there is similar kind of concept(like
hard link ) in FAT32 file system so that i can do same thing in FAT32
file system also

Thanks in advance
Manish K. Sharma

2

No, FAT32 does not support hard links or anything like it.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Manish Sharma
Sent: Thursday, April 14, 2005 10:13 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] hard link concept

hi all,
In my project, I want to link from one file to another for this I
use hard link concept and it works well on NTFS file system but it will not
work on FAT32 can there is similar kind of concept(like hard link ) in FAT32
file system so that i can do same thing in FAT32 file system also

Thanks in advance
Manish K. Sharma

3

It is not possible to have hard links on FAT. FAT has no file descriptors
and keeps all file information in the dirent.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: “Manish Sharma”
To: “Windows File Systems Devs Interest List”
Sent: Friday, April 15, 2005 9:13 AM
Subject: [ntfsd] hard link concept

hi all,
In my project, I want to link from one file to another for
this I use hard link concept and it works well on NTFS file system but
it will not work on FAT32 can there is similar kind of concept(like
hard link ) in FAT32 file system so that i can do same thing in FAT32
file system also

Thanks in advance
Manish K. Sharma

—
Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

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4

FAT16/FAT32 knows “hardlinks” indeed. They are referred to as “crosslinked
files”. But the point is that on FAT this as an error *in the* file system,
whereas on NTFS this is a feature *of the* file system.

In DOS times on FAT there was a virus called “Creepy Death”. Actually it did
nothing destructive as long as it was resident. It kept its own version of a
FAT somewhere on the disk and routed all executables through it, basically
(that is, all executables were routed through one FAT entry - i.e. a
crosslinked file). If you removed the virus, all EXEs were crosslinked to
some file (senseless for the loader).

If you could get you FS driver to do the same for FAT it might be possible
to achieve what you want, but:

  • It would be against the specification
  • It’s contrary to the concept of FAT
  • It only works on your running system - not offline from DOS or so

So *technically*, I believe, it would be possible to enforce this. But in
reality there are more factors to consider than your running system with a
substitute driver. My advice: don’t try it :wink:

Regards,

Oliver

hi all,
In my project, I want to link from one file to another for
this I use hard link concept and it works well on NTFS file system but
it will not work on FAT32 can there is similar kind of concept(like
hard link ) in FAT32 file system so that i can do same thing in FAT32
file system also

–

May the source be with you, stranger :wink:

ICQ: #281645
URL: http://assarbad.net

5

:slight_smile: If I remember correctly, the first DOS virus which did it was DIR2 and it was very inovative idea then.

Actually, crosslinked files are considered as a serious FAT corruption and this approach would be very dangerous. Imagine user boots other OS without “virus” installed. Imagine user would use some volume imaging utility as Ghost which interprets file system on its own.

When a FS filter solution is acceptable, why not use OS supported way instead? I mean STATUS_REPARSE and keep hardlink database in a file or the registry. Such a filter is rather simple in terms of FS filters development.

Best regards,

Michal Vodicka
UPEK, Inc.
[xxxxx@upek.com, http://www.upek.com]

From: xxxxx@lists.osr.com[SMTP:xxxxx@lists.osr.com] on behalf of Oliver Schneider[SMTP:xxxxx@gmxpro.net]
Reply To: Windows File Systems Devs Interest List
Sent: Friday, April 15, 2005 1:28 PM
To: Windows File Systems Devs Interest List
Subject: Re: [ntfsd] hard link concept

FAT16/FAT32 knows “hardlinks” indeed. They are referred to as “crosslinked
files”. But the point is that on FAT this as an error *in the* file system,
whereas on NTFS this is a feature *of the* file system.

In DOS times on FAT there was a virus called “Creepy Death”. Actually it did
nothing destructive as long as it was resident. It kept its own version of a
FAT somewhere on the disk and routed all executables through it, basically
(that is, all executables were routed through one FAT entry - i.e. a
crosslinked file). If you removed the virus, all EXEs were crosslinked to
some file (senseless for the loader).

If you could get you FS driver to do the same for FAT it might be possible
to achieve what you want, but:

  • It would be against the specification
  • It’s contrary to the concept of FAT
  • It only works on your running system - not offline from DOS or so

So *technically*, I believe, it would be possible to enforce this. But in
reality there are more factors to consider than your running system with a
substitute driver. My advice: don’t try it :wink:

Regards,

Oliver

> hi all,
> In my project, I want to link from one file to another for
> this I use hard link concept and it works well on NTFS file system but
> it will not work on FAT32 can there is similar kind of concept(like
> hard link ) in FAT32 file system so that i can do same thing in FAT32
> file system also

–

May the source be with you, stranger :wink:

ICQ: #281645
URL: http://assarbad.net

Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@upek.com
To unsubscribe send a blank email to xxxxx@lists.osr.com