Muen License (was: Muen Separation Kernel Might not be the Only option)

Adrian-Ken Rueegsegger ken at ...309...
Tue May 17 14:10:17 CEST 2016

Hi Martin,

On 05/16/2016 01:30 PM, Martin Vahi wrote:
> I just found it, but it seems that unlike
> Muen, it is under GPL version 2, not version 3,
> which means that it can be used for aggregate
> works that do not link to it without putting
> the rest of the parts under GPL. Just like
> the ordinary Linux kernel can be used for
> running proprietary software without
> affecting the license of the proprietary software.

The license of the Muen kernel and the Muen toolchain is indeed GPLv3
but this does *not* cover components or subjects running on top of the
Muen Separation Kernel. A note clarifying the intent is part of the
projects COPYING file, see [1]. It is similar in spirit to the note in
the Linux COPYING file [2] but we made it very explicit in an attempt to
avoid any confusion.

Thus it is perfectly possible (and legal) to develop closed-source
software that runs as a component/subject on top of the Muen kernel. We
are also careful when choosing licenses for libraries that may be
re-used by other parties, e.g. the shared memory channel library
'libmuchannel' is licensed under BSD [3].

We chose the GPLv3 for the Muen project so the community can benefit
from development of the kernel and the toolchain.

> The XstratuM seems to be some European Space Agency
> project. I haven't studied the source, but at first
> glance it seems to be written in C, not Ada, which
> means that the de facto proprietary (GPL v3) AdaCore
> Ada implementation, the only thoroughly maintained
> Ada implementation (id est from commercial
> development point of view Ada is de facto
> proprietary programming language) a truly open,
> non-proprietary language can be used.

The Ada compiler GNAT is and has been part of GCC, which is distributed
by the Free Software Foundation, for quite some time [4]. To quote [5]:

  The compiler is licensed under the terms of the GNU GPL 3+ with GCC
  Runtime Library Exception.

So, I fail to see how you arrive at the conclusion that Ada is a "de
facto proprietary programming language".

> the parties, who are not as loaded (with money)
> as the military-industrial complex is, might also
> have a chance.

The home of the Muen Project is the University of Applied Sciences HSR
[6] in Rapperswil, Switzerland which is clearly not part of any
military-industrial complex ;)

> Thank You for reading my letter. :-)

Frankly, I was a bit surprised by your email, as we have discussed the
Muen license in a private email conversation several months ago where
you indicated that I was able to clarify the situation to your
satisfaction. If you have further questions about this topic feel free
to pick up our earlier conversation or ask questions on the Muen project
mailing list [7].


[1] -;a=blob;f=COPYING
[2] -
[3] -;a=blob;f=components/libmuchannel/COPYING
[4] -
[5] -
[6] -
[7] -

More information about the users mailing list