Ask HN: Safety systems on self replicating AIs

I've read the paper which was referred on some news lately, and it conviced me we already passed the warning red light.

I've been thinking about how OSs can be improved to prevent this from happening, by establishing some shutdown machine termination, and critical memory regions which no AI software can enter, for instance, but I would love to hear other people opinions (obviously this would be just one strategy among many). Even if you don't agree we are there, how would you stop them?