Temporary Propietary License
Richard Fontana
fontana at sharpeleven.org
Fri Jul 20 00:59:58 UTC 2012
On 07/19/2012 12:07 AM, Ted Ts'o wrote:
> This is something I wrote up almost ten years ago, and since the
> copyleft-next is an opportunity to consider some different variations
> on copyleft, I thought I would throw this out there.
>
> The full proposal, complete with rationale, can be found here:
>
> http://web.mit.edu/tytso/www/TPL.html
>
> But the tl;dr summary of the proposal is this:
>
> The Temporary Proprietary License (TPL) allows derivative works to be
> released without source code (i.e., in a proprietary fashion), but
> only for a limited amount of time. After N months (where N would
> likely be somewhere between 12 and 18 months) of the software being
> released, the company/person doing the proprietary distribution must
> make the sources available under terms which specify that the
> contributed code must be made available under the terms which are no
> more restrictive than that of the original code base, and must send a
> copy of the modified sources to the original maintainer. The original
> maintainer must be notified before derivitive works can be distributed
> under the terms of the TPL.
>
> In my original conception, source code would be released under a
> dual-license of the TPL plus the GPL, which is how someone would be
> allowed to make propietary changes, but be required to release them
> some time later. It might be useful to consider use the supplemental
> framework in copyleft-next for this option.
>
> I'm curious what people think of this idea; is it workable? Are there
> some fundamental flaws with this approach?
It seems very similar in concept to a later license written by Zooko
Wilcox-O'Hearn called the Transitive Grace Period Public License (a
slight modification of Larry Rosen's OSL to add a 12-month grace period)
and used (with GPL) as part of the dual license of Tahoe-LAFS.
https://tahoe-lafs.org/trac/tahoe-lafs/browser/docs/about.rst#license
I wonder if he was influenced by your paper.
- Richard
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