So how did they do it in 880K?

[commodorejohn]

It's simple: you just have to not be a lazy ass, know what you're doing, and never settle for "eh, whatever, we'll just up the requirements another 2x."

Unfortunately, nobody does that anymore.

[commodorejohn]

Hell, virtualization and hypervisors were created in the 1960s when computers didn't have "memory" as we understand it - they stored "words" rather than bytes and kilobytes.

Indeed. Hell, even Windows NT was openly based on VMS, which dates from 1975 and ran in 40MB disk space and 6MB RAM. Most of the advances in desktop operating systems since the mid-'80s have been putting progressively simpler interfaces on top of mainframe tech from the '60s-'70s...