L4 microkernel: very small kernel, consists only of the scheduler, memory management and IPC.
- Commercially used to build complex systems with high emphasis on security
- Smartphones (Simko-3 -- Deutsche Telecom), laptops (genua mbh)
- Existing implementations: Fiasco/OC + L4RE (Opensource, GPL, amd64 and arm), seL4 (soon-to-be-opensourced)
Existing ports: L4Linux, L4Android, L4OpenBSD (public development stalled)
The idea is to run the FreeBSD kernel as an L4 userland application -- this will allow, for example, to use FreeBSD's features like GEOM, fast IP stack, ZFS as L4 services.
Implementation requires certain modifications of the FreeBSD kernel. genua mbh is going to opensource the modifications to L4OpenBSD port that are used internally, this will greatly help to make a port of FreeBSD.
The existing port for OpenBSD is here, although it is 32-bit only and for the older OpenBSD version. genua mbh is going to opensource its changes, details will follow later.
Currently I have some progress on it, but I cannot make my changes public.