Subject: Re: multiple licences
To: Thomas Michael Wanka <tm_wanka@earthling.net>
From: Miles Nordin <carton@Ivy.NET>
List: netbsd-advocacy
Date: 02/21/2000 00:54:27
On Mon, 21 Feb 2000, Thomas Michael Wanka wrote:
> if a given piece of code is published under the BSD licence the
> publisher should still have the right to publish the same piece of
> code under e.g. the GPL and vice versa
I'm not exactly experienced but my understanding is as follows.
o It is possible to offer code under multiple licenses and tell the user
``take your pick'' among the offered licenses.
o Sometimes, if a piece of code's original license is permissive enough,
one can change a program slightly and redistribute it under a new
license, provided that the new license does not violate the original.
For example, when IBM or NetApp modify the BSD code, they redistribute
it under a traditional corporate license, which is more restrictive
than the BSD license but does not violate it. One could also
distribute a hacked BSD under a license that demands source code be
available to all descendent revisions. but not the GPL, because the
GPL makes demands that violate provisions in the BSD license (ex.,
advertising clause)
o Each piece of code has not only a license, but an owner to which the
license is assigned. Only the owner or assignee can change the license
on a piece of code to something that conflicts with the originial
license. For example, the BSD license on the 4.4BSD-Lite2 tapes is
assigned to The Regents of UC, so UC was able to _change_ the license
and _remove_ the advertising clause on these tapes. Likewise, to
contribute to gcc you must assign your license to the FSF, so the FSF
can change the license on your contribution to something notGPL later
on if they want to. If you are the asignee of your BSD license, you
can later change the license to GPL or offer users their choice. If
you assign your license to the Regents or to TNF (``code contributed to
TNF by T.M. Wanka''), then you cannot make this change, but TNF or
the Regents can make the change for you, which is better in some
circumstances. For example, NetBSD's BSD licenses are assigned to a
sundry cast of hundreds--individuals, UCB, TNF... This makes the
amorphous license on NetBSD as a whole harder to change. That's why
the gcc folk insist on a license assignment.
o When the license on a given revision of code fragment that's already
been distributed, changes, then as a user you can still have the old
license as an option. Because of this, licenses on already-distributed
code generally change only in the more-permissive direction, because
any other change would be meaningless. If a license is made more
restrictive, it usually only includes future revisions. This fact is
intuitive but important--it's why, for example, OpenSSH exists. A
change in licensing terms forked the project at an old revision that
still offered the ``free-er'' license. The GPL is designed so a more
restrictive license on a future revision would conflict with the GPL,
so only the asignee can make the license on future versions more
restrictive. With the BSD license, anyone (IBM, NetApp) can make the
license on future versions more restrictive.
--
Miles Nordin / v:+1 720 841-8308 fax:+1 530 579-8680
555 Bryant Street PMB 182 / Palo Alto, CA 94301-1700 / US