Comment Re:Who uses it? (Score 0) 20
The only real success story for building an OS around a virtual machine and changing CPU architectures underneath is IBM System-i (formerly AS/400) with the TIMI virtual machine. They've had multiple transparent CPU architecture changes without breaking application compatibility.
Those CPU architecture changes have come with hardware translation glued on the front end of the processor. The hard work is being done in silicon, not in software. You can't just run the system on a random CHRP or PREP PPC machine for example despite the underlying CPU having been PPC. Even if you had drivers for the system the CPU wouldn't do what is needed.