USB drives and device names

[John Abreau]

On Fri, January 25, 2008 4:30 pm, Dan Coutu said:
> On Linux a USB connected hard drive appears as a SCSI device. But the
> naming of the device seems to 'float' based on who-knows-what criteria.
>
> So for example yesterday I saw an USB drive device change from being
> /dev/std to /dev/stc. Talk about unique! I've seen the letter increment
> before when you disconnect a drive and reconnect it (the USB connection
> is what I'm referring to here) but never have I seen it decrement.
>
> Is there any kind of algorithm that could be used, perhaps within a
> shell script, in order to reliably mount a USB drive without fail and
> without having to guess at the device name?
>


You can always mount the drive based on its label. For instance,
if the partition is labeled "FamilyPhotos", you can mount it via

    sudo mkdir /mnt/temp
    sudo mount -L FamilyPhotos /mnt/temp

Gnome already does something similar; when it automounts a usb drive,
a cdrom, etc., it creates a mount point for it under /media, based
on its label, and then mounts it there. It also adds an entry for it
to /etc/fstab, with the attribute "managed".

If the filesystem on the usb drive is ext3, you can label it with
the command "e2label"; if it's a dos vfat filesystem, you can label
it with the "mlabel" command from the mtools package.


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