The Muen Separation Kernel is the world's first Open Source microkernel that has been formally proven to contain no runtime errors at the source code level. It is developed in Switzerland by the Institute for Internet Technologies and Applications (ITA) at the University of Applied Sciences Rapperswil (HSR). Muen was designed specifically to meet the challenging requirements of high-assurance systems on the Intel x86/64 platform. To ensure Muen is suitable for highly critical systems and advanced national security platforms, HSR closely cooperates with the high-security specialist secunet Security Networks AG in Germany.
The webpage contains instructions for building the kernel yourself, for installing it in a virtual machine, and for running it on real hardware.