Temporary Propietary License

Ted Ts'o tytso at mit.edu
Thu Jul 19 04:07:19 UTC 2012


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?

Thanks,

						- Ted






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