You can get Azul's Linux patches here: http://www.managedruntime.org/ http://www.managedruntime.org/ From what I understand, the main win is that they use nes

You can get Azul's Linux patches here: http://www.managedruntime.org/ http://www.managedruntime.org/ From what I understand, the main win is that they use nested page tables to let the JVMs handle page faults directly, which is how they implement high-performance read barriers. I don't know a lot about garbage collection, but read barriers seem to be the essential piece for implementing real-time (which really should be called "non-blocking") GC. There's a good discussion on LtU about this: http://lambda-the-ultimate.org/node/4165 http://lambda-the-ultimate.org/node/4165 [edit] I should mention how this relates to Lisp operating systems: if you replace the virtual memory system with a garbage collector (ie push the GC into the kernel), you can get the same effect but without needing nested page tables/VT-x/RVI, even for user-space processes. It should also be more efficient and waste less memory on fragmentation than going through a dumb VM.