[Asterisk-Users] Re: Help with GPL license of Asterisk

[Gerald Henriksen]

On Thu, 02 Oct 2003 11:26:56 -0700, Jan Rychter <jan at rychter.com>
wrote:

>Having worked with GPL software quite a bit, also in the commercial
>world, and having gotten some legal advice, I believe that the
>"anti-patent" clauses in the GPL and LGPL are quite possibly the biggest
>problem preventing the use of GPL'd software by commercial entities,
>much bigger than the "pass on the source and the rights" requirement.

Not really.  Certainly it hasn't stopped lots of companies big and
small from releasing GPL software.

>As I understand it (and as my legal counsel advises me) this effectively
>means that if I distribute GPL/LGPL code, I have to make sure that its
>distribution and re-distribution is not restricted by patents (or other
>restrictions).

No, simply because that would be impossible (both because you would
never be able to program given the number of patents you would have to
search, and because it is entirely probable that no software is
entirely patent free).

What you can't do is knowingly license some source code/software under
the GPL/LGPL if you are already aware of any patent or other issues
that would in any way conflict with the redistribution of that code.

>If the code in question contains parts which some patents lay claim to,
>restricting distribution, then I must not distribute the code at
>all. 

Correct.  The GPL/LGPL allow no further restrictions other than that
of the GPL/LGPL itself.  

>It is needless to mention that it is impossible to me to verify that no
>patents (worldwide!) lay claim to the code I'm distributing and impose
>restrictions upon its distribution. Sooner or later I'm going to find
>out that I do not comply with the GPL, because I distribute GPLd code
>even though there are patent restrictions that apply to it.

Possibly.  But those same issues apply to any software whether open
source or closed source.  Regardless of the license used patents would
still apply, and would be enough to force you to stop distributing
your software without an appropriate license (and possibly fee).

>An example of a particularly clear case of this problem is the XviD code
>(http://www.xvid.org/), which is GPL-licensed. It seems to me that the
>authors (copyright holders, to be precise) may distribute the software
>under any license they choose, but nobody else is allowed to
>re-distribute it, because they would be violating section 7 of the GPL,
>as the MPEG-4 compression is (in some countries) covered by patents
>requiring royalties to be paid.

Wrong.  The authors of xvid cannot license it under the GPL/LGPL
because MPEG-4 is known to have patent license issues.  In other words
the patent issues place a restriction on distribution that violates
the GPL, hence it cannot be GPL.

This is not unique to xvid, the same issue applies to any of the mp3
decoders (like xmms) which cannot be GPL/LPGL licensed which is why at
the very least Red Hat has removed those programs from their
distribution.

If those authors want to release open source codecs then they need to
either:

a) use another open source license that does allow restrictions on
further redistribution (I believe the BSD license falls into this
category but I could be wrong).

b) arrange for an exemption for any GPL software from those patents. 

c) implement a codec with no known patent issues (like ogg vorbis).

>This is an issue which is very often overlooked in the hot GPL
>debates. However, in the commercial world, it is possibly the most
>important one.

Not overlooked, it is just not an issue.

>Conclusion (IMHO of course): if you have the choice, use a license that
>is OSI-compliant but does not have the "anti-patent" clause. Or has it
>phrased differently.

It all depends on what your goal is.

Remember that the GPL also offers protection to companies.  One of the
reasons companies like IBM and SGI are releasing some of their stuff
under the GPL is precisely because it does protect them from having
their competitors simply take the technology and incorporating it into
their non-open source software.