[sane-devel] Epson non-free backend

Julien BLACHE jb at jblache.org
Thu Aug 28 15:18:04 UTC 2008

Martin Rehn <martinrehn at inbox.com> wrote:


The following contains information I gathered about epkowa in the last
years. It's all from memory so hopefully Olaf will correct/complete as
needed :)

> This is a newbie question. I'm looking for some insight into why some of the 
> Avasys/epkowa drivers for Epson rely on a proprietary and binary-only 
> plug-in, while many others do not? Are there particular chipsets that have 

Some scanners were presumably sub-contracted to a third party by
Epson; as a result they do not implement the Epson protocol for
scanners natively. As it seems Epson really wants to use this
protocol, they came up with interpreter libraries that do the

As you can see in the SANE list of supported scanners, some Epson
scanners are supported by the snapscan backend and not the
epson/epson2 backends.

> restrictions, preventing Epson from releasing free drivers? What exactly is 

Epson does not have the rights to the IP contained in the interpreter
libraries that are the property of the sub-contractor or another.

> the non-free portion of the driver doing; is that essentially the entire 
> driver or just a small part? Is there any will on the part of Epson to free 

It's a small part, but it's the part that talks to the scanner, so...

> any of those drivers? Anyone else here who is working on free replacements? 

We've tried to talk to Epson over the years, and so far that did not
succeed to the best of my knowledge.

As for a free replacement, it was my understanding that the epson2
backend would maybe try to support those scanners, but I may be wrong

> My question boils down to asking whether the Epsons with non-free drivers 
> should be avoided or not, given that I would be fine with using a non-free 
> driver for the moment, but would rather not be bound to it in the long run.  

As anything undocumented that ships only with a proprietary,
binary-only driver, yes, it should be avoided. Relying on the epkowa
backend will come back in your face at the worst possible moment.

Newer versions of iScan! require newer versions of the interpreter
libraries that are only available for some of the latest models. So
far Epson has not committed to providing updated libraries for the
older models. (though Olaf told me he was trying to obtain that)

Olaf is generally helpful and does everything he can possibly do to
help, including forwarding feedback to his management. But there's
only so much he can do, unfortunately. He's not responsible for the
binary-only bits which are provided by third parties he has no control

(that was the "do not pester Olaf" disclaimer - I did so already :)

> I would be willing to do my part to reverse-engineer and replace the non-free 
> part of the driver if that would be more or less straightforward. (I have not 
> yet bought a scanner, but in my area it seems hard to get by any model that 
> does what I want, and that also has open source drivers, at a reasonable 
> price -- and that's true not only for the Epsons.)

Have fun :)


Julien BLACHE                                   <http://www.jblache.org> 
<jb at jblache.org>                                  GPG KeyID 0xF5D65169

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