L4Linux

L4Linux is a variant of the Linux kernel that is being altered to the extent that it can run virtualized on the L4. L4 is a microkernel and the L4Linux kernel runs a service. L4Linux is not a fork but a variant and is binary compatible with the Linux/x86 kernel, thus it can replace the Linux kernel of any Linux distribution.
L4Linux is being developed by the Dresden Real-Time Operating System Project (DROPS) to allow Real-time and Time-sharing-Programs to run on a computer in parallel at the same time.
L4Linux also allows the setting up of a virtualized environment vaguely similar to Xen or KVM, but there are a couple of significant differences between the intention of Xen and L4Linux.
L4Android.
L4Android is a fork of L4Linux which encompasses the modifications to the main-line Linux kernel for Android. It is a joint project of the operating systems group of the Dresden University of Technology and the Chair for Security in Telecommunications of the Berlin Institute of Technology.