From: Richard Braakman <[EMAIL PROTECTED]>
> But "If you distribute this software without source code, you must
> accompany it with a written offer, valid for at least three years,
> to give any third party, for a charge no more than your cost of
> physically performing source distribution, a complete machine-readable
> copy of the corresponding source code, to be distributed under the terms of
> Sections 1 and 2 above on a medium customarily used for software
> interchange" apparently does not. Why not?
Because it implements an explicit requirement of DFSG section 2, the
availability of source code. This particular GPL clause acts to compel
the disclosure of source for modifications and derived works that you
distribute. The DFSG does not require you to write a license that always
keeps modifications free, but nor does it prohibit such licenses.
There are other such clauses that we also allow - for example, this one from
the MPL which requires contributors to license their patents. This either
implements an implicit requirement that you be able to legally use the
software, or it implements DFSG section 5 regarding discrimination.
2.2. Contributor Grant.
Each Contributor hereby grants You a world-wide, royalty-free,
non-exclusive license, subject to third party intellectual property
claims:
(a) to use, reproduce, modify, display, perform, sublicense and
distribute the Modifications created by such Contributor (or
portions thereof) either on an unmodified basis, with other
Modifications, as Covered Code or as part of a Larger Work; and
(b) under patents now or hereafter owned or controlled by
Contributor, to Utilize the Contributor Version (or portions
thereof), but solely to the extent that any such patent is
reasonably necessary to enable You to Utilize the Contributor
Version (or portions thereof), and not to any greater extent that
may be necessary to Utilize further Modifications or combinations.
I suspect I could find something similar in most licenses that are already
accepted under the DFSG. So, I think that DFSG section 1 can't be interpreted
to prohibit reasonable implementations of the DFSG's own goals.
Thanks
Bruce
