Acceptable patent license for free software?

MJ Ray mjr at
Thu Apr 3 14:04:52 UTC 2008

Simon Josefsson <simon at> wrote:
> Hi!  I'm writing guidelines for IETF document authors on how to achieve
> free software compatible copyright and patent licenses [1].  [...]
> [1]
> Does anyone have some references to any patent license that have been
> deemed acceptable to some free software projects?
> Going further, is there some kind of patent license that free software
> would _prefer_ (as opposed to just _accept_)?

Thank you for writing guidelines.  I cannot answer the above two
questions.  I am mostly ignorant of software patent licensing because
I believe pure software is a sequence of mathematical expressions
which cannot be invented, only discovered.

> To give a concrete example of what I'm thinking of:
> There is one patent license in <>:
>   Subject to the terms and conditions of this License, Google hereby
>   grants to You a perpetual, worldwide, non-exclusive, no-charge,
>   royalty-free, irrevocable (except as stated in this License) patent
>   license for patents necessarily infringed by implementation (in whole
>   or in part) of this specification. If You institute patent litigation
>   against any entity (including a cross-claim or counterclaim in a
>   lawsuit) alleging that the implementation of the specification
>   constitutes direct or contributory patent infringement, then any
>   patent licenses for the specification granted to You under this
>   License shall terminate as of the date such litigation is filed.
> This patent license is a reciprocal license, but is fairly limited in
> scope.
> Would that be acceptable to free software projects?

No, I think - to call it free software, I would want to be able to use
the patent-covered software "for any purpose" and not just
"implementation of this specification" like in the above.  Compare

Hope that explains,
MJ Ray (slef)
Webmaster for hire, statistician and online shop builder for a small
worker cooperative
(Notice tel:+44-844-4437-237

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