[License-discuss] dual licensing and the Open Source Definition

Ben Tilly btilly at gmail.com
Fri Dec 13 15:33:47 UTC 2013

Your fundamental confusion is that you don't understand how dual
licensing works.

A license gives you a set of terms under which you are allowed to do
something that you would not be allowed to do without the license.
Dual licensing is the situation where you have a potential choice of

All cases where you can "buy out" of a GPL license are dual licensing
situations.  The company owns the copyright to the license, and gives
you a choice of an open source license for free, or a commercial
license for money.  There is nothing in the GPL saying that you can do
this, and there is nothing you could put in the GPL saying that you
could not do this either.  The GPL is popular for this purpose because
it is both well-understood, and inconvenient for many commercial
purposes.  (So there is incentive to "purchase the upgrade" to a
commercial license.)

With that cleared up, here are the answers to your questions.

1) The GPL is perfectly fine under the OSD.

2) No license with the kind of conditions that you want would qualify
as open source.

On Thu, Dec 12, 2013 at 1:46 PM,  <zgilboa at culturestrings.org> wrote:
> Greetings,
> As per the Open Source Definition, commercial use of Open Source software
> must be permitted, yet "the license shall not require a royalty or other fee
> for such sale."
> One interesting side-effect of the above is that software can be released
> under a strong copyleft license, for instance the GPL, and yet be
> accompanied by the option to "buy one's way out of the license," thereby
> releasing the buyer from any and all obligation to make the modified source
> available to the public.  For a possible real-life example please see the
> cygwin project, and specifically the clause concerning the project license
> (found under "Cygwin License Contract" at
> http://www.redhat.com/services/custom/cygwin/, and mentioned here for
> illustration purposes only).
> In light of the above, and given the guarantee of the Open Source Definition
> with respect to source availability and fields of endeavor, a couple of
> questions arise:
> 1) to what extent does the GPL meet the OSI promise regarding the source of
> Open Source Software remaining open?  After all, if vendors can take GPL'ed
> software and buy their way out of the license so that binaries, with or
> without changes, can be distributed without restriction and without a
> corresponding source, then something is probably not working the way it was
> originally intended.
> 2) Consider the case of an individual entrepreneur who created a software
> library, and who would like to require vendors of commercial products that
> _depend_ on that library to pay a _one-time fee_, but otherwise be permitted
> to use the library or distribute it in any way they see fit without
> additional charges, and provided that the original source code, along with
> all changes that were applied to it, remain available to the public.  Would
> that author be able to release his/her library under an OSI-approved
> license?  Having gone through the various licenses on the site, I was unable
> to identify a single license that adequately meets this scenario.
> I believe that (2) could be of interest to independent developers who either
> prefer not to, or are unable to rely on voluntary donations for the
> continuing development of their projects.  Then again, it seems to me that
> the possibility to regulate one-time charges for commercial use from
> _within_ a license should be much preferred over a de facto option to bypass
> the license altogether.  Ultimately, then, the purpose of this post is to
> discuss, and hopefully find out, whether a license can be written with the
> above scenario in mind, and yet remain in compliance with the Open Source
> Definition.
> Looking forward to your thoughts,
> z. gilboa
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