Re: Copyleft variation of MIT license

["Suraj N. Kurapati" <skurapat@ucsc.edu>]

Florian Weimer wrote:
> * Suraj N. Kurapati:
> 
>> The above copyright notice and this permission notice shall be
>> included in all copies or substantial portions of the Software.
>> These copies and portions shall be distributed along with their
>> source code.
> 
>> Is that better?
> 
> Perhaps, but it's only a very, very weak copyleft license.  In the
> end, you could probably use the plain MIT license with a similar
> effect.

True. In order to make the copyleft a bit stronger, I borrowed some
conditions from the SleepyCat license. Here is the new conditions
paragraph:

All copies and substantial portions of the Software (the "Subsets")
must include the above copyright notice and this permission notice,
and must be distributed with their source code or with information
on how to obtain their source code.  This source code must include
all changes, if any, made to the Subsets, must be available for no
more than the cost of distribution plus a nominal fee, and must be
freely redistributable under these conditions.


Allow me to explain my understanding of the above conditions:

* "source code must include all changes, if any, made to the Subsets"

This prevents people from keeping some or all of their modifications
secret.

* "must be available for no more than the cost of distribution plus
a nominal fee"

This prevents people from keeping the source secret by charging
ridiculous amounts of money for access to the source.

* "must be freely redistributable under these conditions"

This establishes the conditions paragraph as the base requirements
for distribution of my code. However, I am afraid that this might
prevent people from releasing my code under a superset license...

I am not very sure about this one. What do you think?

Thanks for your consideration.

> On the other hand, the third version of the GNU GPL will very likely
> be compatible with attribution requirements.  Perhaps you should
> simply wait for that.

Thanks for your suggestion. I will definitely consider GPL3 when it
has been released.