Subject: Re: termless copyright and patents
From: "Ben Tilly" <btilly@gmail.com>
Date: Mon, 9 Oct 2006 11:42:04 -0700

On 10/9/06, stephen@xemacs.org <stephen@xemacs.org> wrote:
> Ben Tilly writes:
>
>  > The key here from my point of view is 3.  You should not reasonable
>  > expect me to attempt to modify your GPLed code to make it infringe on
>  > another patent that you have.  Therefore there is no reliance if I do
>  > so, and you cannot be held to your promise to not sue me.  Ditto if I
>  > take your GPLed code and modify it by borrowing from some non-GPLed
>  > code of yours.
>
>  > However you should reasonably expect me to copy, modify and distribute
>  > your code if you release it under the GPL, so if you sue me for that I
>  > should be able to hold you to your promise. :-)
>
> I don't understand what you're trying to say.  My expectation, as I
> said in discussing whether GPLv2's implicit license is the same as
> GPLv3d2's explicit covenant, is that claims actually implemented in
> the software *will* be used in modified software.  However, I expect
> hackers to exercise due diligence and in particular avoid practicing
> claims in my patent that are not embodied in the software.

That fits with my understanding.  I'm trying to apply my limited
understanding of the concept of reliance to explain why the GPL
protects some modifications and not others.

> The patent number(s) and the claims that I believe are covered by the
> covenant or implicit license, will be listed in the permissions notice
> for your convenience.

Is this necessarily so?  I think not.  In fact I think that part of
the objection people have to the patent covenant in the GPL v3 (now
that they understand it is there) is the possibility that at a large
organization (eg MIT), one group can release software that infringes
on a patent issued elsewhere in the organization.  (A patent which MIT
may be bound by contract to not offer permission on.)  MIT comes to
mind in this regard because I believe it was them that were not long
ago floating a license with an explicit patent disclaimer because of
their fear of exactly this kind of situation happening.

> How does that compare to what you have in mind?

Very well, except that I don't think that patent holders are always
going to be so organized about their notices.

Cheers,
Ben