On Wed, Aug 1, 2012 at 8:02 AM, Luis Villa luis@tieguy.org wrote:
On Tue, Jul 31, 2012 at 8:25 PM, Theodore Ts'o tytso@mit.edu wrote:
On Tue, Jul 31, 2012 at 10:40:41PM -0400, Richard Fontana wrote:
It is intended to be strong copyleft. This is a fixed goal.
Just to clarify, when you say strong copyleft, you mean in the GPL vs LGPL sense, right?
People have been using "stronger" and "weaker" in other senses (i.e., whether there are more restrictions, such as the anti-Tivo clause) --- i.e., GPLv3 is "stronger" than GPLv2, or GPLv2 is "stronger" than BSD.
Personally, I don't really like "strong" and "weak" because it's rather imprecise, and it doesn't take into account the multidemensional nature of things; that is, it's not a single continuum of where certain licenses are "stronger" than others, and where someone might try to say that the "strongest" copyleft is best; licenses can't be strictly ordered!
Historically, that has been the case, but given the convergence in patent termination clauses, notification requirements, and compatibility, the most recent versions of the major licenses (Apache, MPL 2, LGPL 3, GPL 3, AGPL 3, but excluding eclipse) actually can be basically strictly ordered on a copyleft-only basis.
I should add that:
1) It's obviously not a perfectly strict ordering - there are exceptions. But the basic principles and big concepts are now aligned. You can choose a recent-generation license based on level of copyleft, which wasn't the case in the recent past, when, e.g., you might have wanted the patent protections of MPL 1.1 but the copyleft of GPL. There was no way to get those in one package. Now that we're all agreed on the basics of the patent protection issues you can focus on your level of copyleft.
2) I think this is a very good thing - the convergence is the result of experiments by one license being accepted by others (e.g., MPL's defensive patent clause; GPL's termination/restoration clause, etc.). It may make sense to accept copyleft.next changes that would break the weak ordering we currently have only if they are an experiment that would stand a reasonable chance of being adopted by MPL 3, GPL 4, etc.
Luis