I do not know anything about the XstratuM
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 way I understand, the GPL v3 is infectious even, when linking is not done.
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. Add to that the fact that formal verification tools for C and C++ tend to become more available,
http://mbeddr.com https://github.com/mbeddr
the parties, who are not as loaded (with money) as the military-industrial complex is, might also have a chance.
Thank You for reading my letter. :-)
Regards, Martin.Vahi@...427...