| Jeff Abrahamson on 10 Jan 2007 18:24:19 -0000 |
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On Sat, Jan 06, 2007 at 07:07:16PM -0500, jeff wrote: > [17 lines, 89 words, 748 characters] Top characters: _teinso/ > > Apparently a USB hd `became unattached' yesterday. I copied some > files to it. When I fired up today, it was still unattached, but > the files appeared at the mount point. When I got it reattached, > POOF, they were gone. > > Does this mean that they got copied to /mount/dir instead of /dev/sda1? > Where, physically, is /mount/dir when it's not attached to /dev/sda1? The directory /mount/ is a normal directory. When you mount something on top of it (which is how mounts have to work), accesses to the directory become accesses to the mounted thing. So /mount/dir/ still exists, it's just hidden by /dev/sda1 that is now mounted there. Unmount, mv the contents, remount, and mv the contents back. For example, you can copy /usr to a separate partition, then mount taht partition on top of /usr. If you're hacked, you unplug network cables, umount /usr and remount what was there at /usr-hacked. Then you have safe tools to use in /usr (because no one can umount /usr while you're running because the volume is busy) while you look at /usr-hacked. Note that this is an old-school technique for dealing with hacks, from before the days when you could just boot off of CD's (because it is from before the days of CD's). I mention it here as an illustration of how a lot of stuff can hide behind a mount point. Maybe the practical use now is hiding your porn collection from family members or something. ;-) -- Jeff Jeff Abrahamson <http://jeff.purple.com/> +1 215/837-2287 GPG fingerprint: 1A1A BA95 D082 A558 A276 63C6 16BF 8C4C 0D1D AE4B Attachment:
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