Mount hardware to specific location with specified device

My subject probably doesn't make any sense but I wasn't sure how to
word it.

I have 2 external USB 2.0 / Firewire hard-drives and an iPod. I only
turn them on when I need them. The problem I'm running into is that
whichever is the first device to be turned on gets assigned to
/dev/sda. The next device gets /dev/sdb and so on.

I need to assign each piece of hardware it's own device so that my
programs know where to find the correct hardware. For example, when I
turn on my iPod I want it to get /dev/sdc even if I don't have my
hard-drives on. And if I turn on my "2nd" hard-drive first, I want it
to get /dev/sdb instead of /dev/sda

Is this possible?

As it stands right now, every time I turn on one of my devices I have
to manually shuffle around the mount locations because /etc/fstab will
mount /dev/sda to /mnt/ext_hdd regardless of which device it is. And
if it happens to be my iPod, then when I start GTKPod, it can't find
any of my music because it's looking in /mnt/ipod

I guess it doesn't really matter which device gets assigned to
/dev/sda as long as I have some way of telling it which directory to
get mounted to based on the content of the device. So that if
/dev/sda is my iPod, it gets mounted to /mnt/ipod. But if /dev/sda is
my 1st external hard-drive, it gets mounted to /mnt/ext_hdd. But if
/dev/sda is my 2nd exteranl hard-drive, it gets mounted to
/mnt/ext_hhd2


Uh... what else. I'm running RedHat 9, Linux kernel 2.4.20-20.9
(RedHat kernel)

David <blixel@yahoo.com> wrote:
> Is this possible?

Quick answer: no it isn't.
Long answer: if you want to go all the way into hacking the
various device drivers that handles those devices it is possible,
but do that at your own risk.

> to manually shuffle around the mount locations because /etc/fstab will
> mount /dev/sda to /mnt/ext_hdd

Then get them out /etc/fstab and use a more flexible script to mount
what you want where you want.

Davide

blixel@yahoo.com (David) writes:

> I need to assign each piece of hardware it's own device so that my
> programs know where to find the correct hardware. For example, when I
> turn on my iPod I want it to get /dev/sdc even if I don't have my
> hard-drives on. And if I turn on my "2nd" hard-drive first, I want it
> to get /dev/sdb instead of /dev/sda


You can try
http://www.lerhaupt.com/devlabel/devlabel.html
which is an attempt at a proper solution to the problem.

Otherwise, if all of drives are formatted as ext2, ext3, or xfs, you
can identify them by `LABEL=...' in /etc/fstab rather than by device
name. Unfortunately, Linux's `mount' command doesn't recognize volume
labels on other filesystems.

Failing that, you can hack together a script that looks at
/proc/bus/usb and /proc/scsi to try to figure out which device is
attached where.

For more info see
http://groups.google.com/groups?thre...0zoo.cam.ac.uk
--
Stephen Cornell cornell@zoo.cam.ac.uk Tel/fax +44-1223-336644
University of Cambridge, Zoology Department, Downing Street, CAMBRIDGE CB2 3EJ