[sf-lug] Hi; about that printer you got for your setup?

Rick Moen rick at linuxmafia.com
Tue Dec 14 02:03:46 PST 2010

Quoting Alex Kleider (a_kleider at yahoo.com):

> Thanks for the tip(s,) Akkana. My scanner is an Epson (I think it's
> model 2450) that my wife had working very well connected to her MacPro
> before she upgraded to a newer model.

http://www.sane-project.org/sane-mfgs.html#Z-EPSON says:

Model: Perfection 2450
Interface: USB, IEEE-1394 
USB ID: 0x04b8 / 0x0112
Status: Complete
Comment: [none]
Backend: Epson backend (unmaintained), http://www.khk.net/sane/
Manpage: sane-epson, http://www.sane-project.org/man/sane-epson.5.html

> I'm away from it currently but will try what you suggest when I get
> back to it at the end of the week. I don't know much about udev but
> will try to figure things out.

udev is the latest scheme for making the /dev tree autopopulate with
device nodes appropriate for the hardware actually present on a system.

The problem scenario Akkana was describing would only potentially be
present and at issue if you knew that, say, /dev/usb/scanner0 is
supposed to automagically pop into existence the moment you connect your
Epson Perfection 2450 and turn it on, but that device file fails to come
into existence.

In recent Linux systems using udev to populate the /dev tree, you no
longer really want to solve missing-device-file problems using the
traditional 'Well, just use mknod to create it, then' methods from
Pleistocene days, such as is described in the Linux USB Guide, here:

Why not?  Simply because under the udev regime and similar things, the
/dev tree evaporates and is autorebuilt at each reboot.  So, if using
'mknod' to create the missing device files manually, you'd end up doing
it over and over again.  The long-term remedy is to create, in that
case, as Akkana said, a udev rule (recipe, basically), which then does
the manual creation job automatically each boottime.

Aren't you glad we have things like udev to make our systems 'simpler'?  ;->

About sane-find-scanner, see
http://www.sane-project.org/man/sane-find-scanner.1.html, for starters.

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