As Sean Carroll says in his FB page:
The shortest math paper ever reminds us why mathematicians think that P doesn’t equal NP, even if they can’t yet prove it. It’s much easier to check solutions to problems (P) than it is to actually solve them (NP).
Below you can see how a CDC 600 computer looks like around 1964-1969.
[Image credit: Jitze Couperus, Supercomputer – The Beginnings – Flickr]