[ECOS] Project ideas for graduate course

Klaas Gadeyne klaas.gadeyne@fmtc.be
Wed Aug 1 12:14:00 GMT 2007

On Wed, 1 Aug 2007, Andrew Lunn wrote:
>> It does not remove the right to redistribute (modified code) of EML,
>> as long as it stays compatible with the (open) EtherCAT standard (which I
>> think is not so unlogically?)
> And how does that work?
> Say i was to pay for a license and get the GPL source. I make a
> product and sell it, distributing the source, to XYZ. XYZ then hacks
> on the source and adds some features. They make a new product. They
> sell there product to ABC and again distribute the source. ABC does
> some more hacking, breaks compatibility and then sell a product to
> Now only i have signed a license. However i have no control over what
> people do with the GPL code. When FSDS reports the code is no longer
> compatible is my license revoked even though the problem is with ABC
> code? Do you take me to court, i have to take XYZ to court and XYZ has
> to take ABC to court?

The extra clause is (contrary to the GPL or other license) a
non-transferable license, that you only need to sign if you intend to
redistribute the code.  That means that, if you take the code,
alter it and use it internally, you don't even have to sign the
agreement.  If you start redistributing the code (i.e. everyone that
redistributes a modified version of EML), you need to sign the
license agreement that states that your code is conform the standard.

> More questions for the copyright lawyers.....
> Maybe a better way to do this is to throw away the license
> agreement. Instead provide regression test cases which demonstrator
> compatibility to the standard. Anybody hacking on the code should be
> encouraged to run the regression tests to check they have not broken
> anything. If somebody adds new features which comply to the standard,
> you should ask they add more regression tests and feed back the
> changes to you. You can then independently test the changes are good
> and then make a new release. So long as you actively maintain and
> support the code, the chances of somebody forking it are low. Now this
> is what GPL is all about. And it does work. There is huge amounts of
> standards compliant protocol software available under GPL or similar
> licenses.

Even _without_ all the license issues that would be a good thing.
However, when we first implemented EML, the EtherCAT people were still
working on conformance testing.
Also note that the extra clause is an agreement between Beckhoff and
the licensee (and FMTC has nothing to do with that agreement), that
"protects" the licensee from patent claims covering the EtherCAT


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