"Justin T. Gibbs" wrote:

> > > For Mass Storage Devices an alternative would be not to detach the
> > > device at once, but hope that it will reappear shortly.  The serial number
> > > of the device can be used to detect if the same device reappears.
> >
> >Two problems:
> >
> >       What happens if the device never comes back?
> >
> >       What about other SCSI disks (like ones plugged into PCMCIA cards)
> >       which don't have this serial number facility?
>
> Further, the serial number is almost never associated with the
> actual media, but with the physical device.  This means that the
> serial number you get back is usually worthless for removable
> media devices.  You really need to tag the media if you want to make
> this work.

Absolutely, but there are a number of non-removable USB disk available.
As for removable ones I'm sure you could come up with some "fingerprint"
from the superblock.

--

        -- Lennart