Been in my playlist this morning, and, though obvious in some ways, still added some points and leaves me pondering that particular issue more than usual:

At the outset, including for the IBM System three sixty, the computer with a single CPU was not actually multitasking. It was doing the same thing that our brains do. It was jumping back and forth between tasks really fast to make sure it was doing them both adequately. So when we kind of figured out that there was a problem with processing, that there were limits to it. We established very quickly something called a processing bottleneck. That, yeah, there is. It's documented humans do not multitask to begin with, and when we try to multitask, the results are terrible.

via SYSK: Multitasking: Working slower with worse results