That's pretty cool. So it allows the OS to run without a MMU while some (if not all?) of the process isolation benefits. I'd be interesting to learn a bit more about Singularities limitations though, as it doesn't seem to be touched upon that much in these viewgraphs (two bullets) - I'm not entirely convinced software-based process isolation can be made as robust as hardware-based process isolation without some sacrifices in the kind of software you can write.