Unikernels, to me, are basically a resurrection of the type of operating system exemplified by Mac OS 9, 8, 7...  No memory protection; programs just duking it out against each other with pointers in the same arena, like gladiators. But to invoke an image of disciplined violence in the Roman Empire is too kind; really, this is more like a regression to the Stone Age.<p>Right there aren&#x27;t supposed to be multiple applications in there? But eventually there will. Things only <i>start</i> small, as a rule.<p>Look, we have had pages and memory management units since the 1960&#x27;s already. Protection was considered performant enough to be wortwhile on mainframes built from discrete integrated circuits on numerous circuit boards, topping out at clock speeds of some 30 mHz. Fast forwarding 30 years, people were happily running servers using 80386 and 80486 boxes with MMU-based operating systems.<p>Why would I want to give up the user&#x2F;kernel separation and protection on hardware that blows away the protected-memory machine I had 20 years ago.