USB and Scanners

[David Fletcher]

Sorry that this is a bit of a long posting, but I want to explain what I've 
been doing to get a couple of USB devices working for me, and question why my 
Epson Perfection 2450 Photo scanner behaves in an inconsistent fashion when I 
connect it to USB.

Until a couple of weeks ago when I built a new PC, I was still using RH9.

I had problems with using USB on RH9, mounting flash memory devices, and I 
gave up using the printer with USB.

But my USB scanner always worked every time.

Now that I'm using FC3, it's obvious that a hell of a lot of hard work has 
gone into fixing USB, for which I am very grateful to the developer(s). I can 
now reliably use my flash memory devices (the ByteStor branded ones that 
Amazon sells). When I plug one in I always get a device of the same name 
(/dev/sdb1) and mountpoint (/media/USBDISKPRO) so I just right clicked the 
desktop and selected Create New Device, then selected the device from the 
drop down list and set the nice USB memory device icon. Now I can plug in the 
device, right click on the desktop icon, mount, and it's working.

Same with USB->serial adaptors. I tried one out with my Garmin GPS12. Had to 
set the permissions for the device that was created, then put /dev/ttyUSB0 
into the options of GPSMan, and it "just worked". So again, well done to the 
developers. Great job.

But what has happened to scanners? I just can't get it to work reliably. On 
RH9 all I had to do was uncomment a line in epson.conf to get it working. 
When I now switch on my scanner, a device which I think is a symbolic link, 
called scanner-usb-:proc:bus:usb:001:002 pops up in /dev/, which says it 
points to /proc/bus/usb/001/002. Which would probably be fine except that 
when I cycle the power on the scanner, it now pops up in /dev/ with a 
different name, this time it's called scanner-usb-:proc:bus:usb:001:003 and 
points to /proc/bus/usb/001/003.

I found a how-to about getting Epson scanners working with FC3 
http://www.fedoraforum.org/forum/archive/index.php/t-26744.html
but hey, surely this is way too complicated to expect your average person who 
doesn't know a lot about computers to get it working? I write software for a 
living, and I don't understand what's going on.

Why does the scanner keep appearing as different names in /dev/? If it had the 
same name each time, could the name not simply be edited 
into /etc/sane.d/epson.conf or /etc/sane.d/epkowa.conf?

Any chance of making it work like this in future updates?

Thanks for taking time to read all this.

Dave Fletcher