Re: Your backup is unsafe!

Bradley M Keryan (
Mon, 2 Aug 1999 20:40:20 -0400 (EDT)

On Mon, 2 Aug 1999, Kent Overstreet wrote:

> Nathan Hand wrote:
> Ok, I've been following this thread for awhile, and I think I missed the
> first email, but I don't get something: Why do we need to store the 8.3
> version in a backup? It's a pretty simply algorithm to get the 8.3
> filename from the LFN one, why not put the 8.3 version back when you
> restore to the vfat partition, and completely hide the 8.3 filename?

The mapping depends on the order the files are created:

If you create longfilename_a.txt first and longfilename_b.txt second,
then longfi~1.txt=longfilename_a.txt and longfi~2.txt=longfilename_b.txt .

If you create longfilename_b.txt first and longfilename_a.txt second,
then longfi~1.txt=longfilename_b.txt and longfi~2.txt=longfilename_a.txt .

Do a backup without preserving both names and now some programs that rely
on short filenames are hosed.

> Most of the other ideas - symlinks, hardlinks, are *extremely* messy and
> kludgy, and special vfat aware tools. It shouldn't be hard for Linux to
> generate the 8.3 name from the LFN version - when you restore (or are
> writing files to a vfat filesystem in general) you make sure Linux puts
> in both names. In a previous post, I showed how Windows uses directory

It puts in both names, but the short name might be wrong if you're
restoring a backup.

> entries with the hidden, system, and volume label attributes to store
> the LFN name, the entries are then ignored if you boot into, say DOS
> 6.22. Now I could be talking out of my ass, but this whole thing just
> doesn't make sense to me, especially some of the solutions that have
> been proposed. If I'm wrong, feel free to flame me with better
> information :)

I wouldn't mind if the short filenames went away, as long as there were
ioctls so that wine/dosemu/samba/whatever could get at them. I also
wouldn't be surprised if some people did not like such a change...


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