[cbetz]

You're right. The biggest news for operating systems is the fact that the hardware virtualization features on modern processors allow breaking free from the old model.

A modern intel/amd processor lets you virtualize the CPU, MMU, and I/O. Network cards and HBAs can be partitioned into virtual NICs.

Two primary functions of a classic OS are process isolation (i.e. virtual memory) and hardware sharing. But now that these two primary functions have been pushed down into hardware, it has changed the way we think about operating systems considerably.

There isn't much left for a classic OS to do other than provide a common set of APIs for programs to talk through. Yet these days we can statically link even the largest libraries into our exokernels. And hypervisors are capable of using techniques like same-page merging to reduce the memory burden of running many large (exo)kernels at once.

I don't expect the the classic one-OS-running-many-processes model to go away overnight, or possibly ever. But the exokernel model is very compelling for large-scale high performance software services and it will continue to catch on.