[btrask]

I think a unikernel+ProcOS is basically the same as a hypervisor+unikernel, except backwards. The main advantages would be less overhead (one unikernel, instead of N) and greater flexibility (because ProcOS can run on any OS without a VM).

The emphasis on cheap recursion (if it can be achieved) also has benefits like making administrative responsibilities easier to delegate, and preventing various isolation leaks (including scheduling fairness).