Re: (Semi-random) thoughts on device tree structure and devfs

[Iain Hibbert <plunky%rya-online.net@localhost>]

On Tue, 9 Mar 2010, Johnny Billquist wrote:

> The problem you are highlighting is another one, and one which I agree it
> would be nice to have a solution to. But the only solution I can come up with
> is to be able to refer to disks by their name in the disk label, or something
> similar, which is unique per disk, and have no relationship at all with which
> how they are attached to the system.
>
> Something like:
>
> wd0 at umass? label="foobar"
>
> But, as I said, this is another problem, which Masao hasn't at all addressed.
> His solution to his random device enumeration problem is simply a solution to
> a non-problem.

So, you want to be able to mount a disk by the label:

  $ mount -t msdosfs -o label "foobar" /external_disk_foobar

or, if you know the UUID

  $ mount -t msdosfs -o uuid 3478374923723423 ~/thumb_drive

What I'm asking is, why does the "device node" need to be deterministic
and why is this a 'devfs' problem?

The "special" argument to mount(8) does not really need to be a device
node, it could find the right one on its own by checking hw.disknames and
scanning the disklabels..

iain