On Thu, 13 Oct 2005, Ian Kent wrote:

> On Tue, 11 Oct 2005, Dr. Harold K. Brown, P.E. wrote:

> > The issues at play here is when there are several
> > usb-storage devices, (i.e. ipod, memory cards, and
> > cameras) mounted in different order and in different
> > usb ports the (/dev/sd?) assignment is somewhat random
> > from a user standpoint.  

> I thought that device name persistence was one of the issues
> that udev addressed?

Well, sort of, but...  When I use hotplug USB devices (kernel 2.6.11, 
hotplug-0.50, udev-053), the primary device name is whatever the kernel 
feels like, e.g. /dev/sdb1.  However, the rules in /etc/udev/rules.d have 
the possibility of making a symlink with a fixed name, and removing it when 
the device is unplugged. e.g. /dev/ipod -> /dev/sd(whatever).  The hotplug 
machinery also mounts the device for you, and for me this happens reliably. 
In the SuSE distro the mount point is auto-created in the /media directory,
with a name associated with the particular device which seems to change at
every version upgrade, but which at one point included the device's product
ID in hex.  Thus you can make a symlink to the future mount point of the 
specific device.  

Unplugging is another matter -- it's recommended to use "eject" to unmount 
the device, but I've found that hotplug can usually unmount a truly 
non-busy device by itself -- but sometimes it messes up.

Autofs doesn't seem like the best way to handle USB devices, mainly because 
it dismounts on a timeout if the mount point has been unused for a 
(configurable) time, usually set to 5 minutes.

James F. Carter          Voice 310 825 2897    FAX 310 206 6673
UCLA-Mathnet;  6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA 90095-1555
Email: [EMAIL PROTECTED]  http://www.math.ucla.edu/~jimc (q.v. for PGP key)

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