Fwd: [MLton-user] Is mlton free software?

Jesper Louis Andersen jesper.louis.andersen at gmail.com
Tue May 15 14:16:16 PDT 2007

Forwarded because I forgot to hit reply-to-all.

---------- Forwarded message ----------
From: Jesper Louis Andersen <jesper.louis.andersen at gmail.com>
Date: May 15, 2007 10:48 PM
Subject: Re: [MLton-user] Is mlton free software?
To: Bartlomiej Szymczak <rhywek at gmail.com>

It is very close to the original 44BSD license. see


However: The 4th clause in that license (the non-advertising clause)
is the problematic one versus GPL-compatibility and the
one mentioned as problematic in the FSF list. You will note that
such a clause is part of the MLton license.

Parts of the FreeBSD source is still under the 44BSD license, though
all new work is under a 2-clause license (delete statement 3 and 4) See


for further elaboration.

The license used by MLton has a clause stating that the
license itself must be included in derived works. In other words,
you have to give credit to the original project. You are free to fork
the project and create your own, closed, version as long as you
retain the copyright notice and license file.

Does this thing happen in the real world? Yes. Juniper networks sells
routers based on an old fork of FreeBSD. Ciscos IOS include(d/s) a malloc()
implementation from FreeBSD. Several vendors has taken the OpenSSH
code and used it. Is this bad? It depends on your personal views.

A scheme I've often seen regards a BSD-style license is that the developers
are contracted to do some work. It is then the case that the constructed
is released to the world under a BSD-license, while the company forks it at
and takes the software in the direction they want in a closed style. This
makes for
an extremely easy monetization oppurtunity. Partial BSD-license releases are

A variant of the scheme is actually seen with a dual GPL/Proprietary
licensing scheme. See
Troll Tech in Norway and MySQL AB in Sweden. You can get the GPL-version,
but if you
want more rights, you must pay. Again, the scheme depends on personal views.
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