Re: DFSG Freeness of Patent Reciprocity Clauses
On Jan 2, 2004, at 11:00, Walter Landry wrote:
Section 2(b) is just a patent grant. So if a Recipient invokes patent
litigation against a Contributor, then the license effectively becomes
mute about patents. I don't see how that can be DFSG-unfree, since we
have a number of DFSG-free licenses that are mute about patents.
And sometimes software under those licenses is not free. For example,
until recently, the LZW patent got stuff put in non-free.
We must look at the entire freeness of a work, not just the copyright
However, I think patent revoking clauses that are along the lines of:
We won't sue you for patent infringement over your use of this
software, provided you don't sue us for patent infringement on
our use of this software. 
are fine. Note that clauses along those lines have the wonderful effect
of vanishing if, when, and where software patents are not valid.
The OSL one is much beyond this, and thus is non-free. The Apache one
seems to say this, and thus is free.
The IBM one seems too broad as well, but as long as IBM is not actively
enforcing patents on the software, our policy is to ignore patents that
may exist. So we can still treat it as free.
 Please take this with some common sense, not legal sense.