[asterisk-dev] A legal question

[Tzafrir Cohen]

On Fri, Oct 06, 2006 at 10:36:05AM +0200, mbodbg at gmx.net wrote:
> Hello all,
> 
> nearly all modules written for asterisk are distributed under the terms of
> the GPL.
> 
> ...
> 
> * This program is free software, distributed under the terms of
> * the GNU General Public License Version 2. See the LICENSE file
> * at the top of the source tree.
> 
> ...
> 
> In practise that means that everybody can use and distribute that code for
> private or commercial usage. Code Changes must be made accessible for the
> public.  
> 
> In some modules I can find an additional licence notice:
> 
> * A license has been granted to Digium (via disclaimer) for the use of
> * this code.
> 
> What's behind that License Notice? Which additional rights are granted to
> Digium by that License Notice? 

First off, IANAL:

#include <std/disclaim_legal.h>

Software is generally considdered as a copyrighted "art" (the language 
used by the copyright laws). By default the author gets full rights
and the others have basically no rights ("all rights reserved" for
things that are covered by the copyrights law[0]). So the author must
license the software if he wants others to use it.

Such a license can be a strange thing such as "do what you want, but
send me a postcard before starting to use it", "Use it only whene there
is a full moon" or even weirder stuff
(http://www.linuxadvocate.org/articles.php?p=1 ).

Naturally, there is no problem for the author to authorise to some
people to use the software only on a full moon whereas others may use
it only after sending a postcard. In fact, if you sent the author a
postcard, you may be able to use the software even not on a full moon.

That is a dual license. In this case the licenses are:
* GPL (with minor adaptations)
* Proprietary license, that is only granted to people who sent a 
  postcard to^W^W^W^Wwpaid Digium (e.g: the ABE).

Only the author can change the license of the "art" (software, in our
case). The The so-called "disaclaimer" text authorises Digium the legal
power to give a different license to the code.


[0] Reading a book, for instance, is not protected by the copyrights
law. Using a software it. Strange, isn't it?

-- 
Tzafrir Cohen         sip:tzafrir at local.xorcom.com
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