From xen-devel:
I am pleased to announce the release of GUK (Project Guest VM Microkernel), which is an enhanced version of Mini-OS that underpins the Guest VM virtual machine. Guest VM is an implementation of the Java platform, written almost completely in Java, running directly on Xen. Although GUK was developed specifically for Guest VM, it can be used stand-alone in a similar way to Mini-OS.
The main differences between Mini-OS, when originally forked, and GUK are:
•   Support for multiple VCPUS (SMP)
•   Pre-emptive thread scheduling
•   Memory management tailored to a language run time virtual machine
•   Memory ballooning
•   Block device support
•   Suspend/Resume support
N.B. GUK has not been updated with any of the changes to Mini-OS since the initial fork.
The source code, which is licensed under GPL v2, can be found at https://kenai.com/projects/guestvm.
E.g.,
% hg clone https://kenai.com/hg/guestvm~guk guk
I’d like to acknowledge the significant contributions made by Grzegorz Milos and Harald Roeck during summer internships at Sun.
Mick Jordan
Annoucing Release of GUK (Project Guest VM Microkernel)
