How to symlink devfs devices?

[RW]

On Wed, 8 Jul 2009 21:45:48 +0200
Roland Smith <rsmith at xs4all.nl> wrote:

> On Wed, Jul 08, 2009 at 05:49:24PM +0000, Paul B. Mahol wrote:
> > >
> > > Is it possible to create a symlink to a device and use the
> > > symlink in place of the real device name in FreeBSD, especially
> > > in version 7.2?
> > >
> > > 1. A disk
> > >    /dev/camera -> /dev/da0s1
> 
> > devfs.conf(5)
> 
> Geneally, yes. But not in this case, I think. You don't want any old
> usb device to be linked to /dev/camera! USB devices are enumerated in
> the sequence thay are plugged in. So there is no hard guarantee that
> the camera will always be available as da0s1. It might be da1s1 if
> another USB drive was plugged in earlier.
> 
> And not all cameras represent themselves as disk devices (USB mass
> storage). Lots of modern ones use PTP
> [http://en.wikipedia.org/wiki/Picture_Transfer_Protocol].
> 
> So in this case it might be better to use HAL (via hald(8))
> [http://freedesktop.org/wiki/Software/hal]

although if it is a standard usb mass storage device, you can mount it
via it's msdos volume label, or a generic label written to the device by
glabel. Both methods are described in the glabel(8).