Realize you are somewhat summarizing, but: "compatibility with unix" didn't matter in those days. There were many, many OS's, all running on computers so expe

Realize you are somewhat summarizing, but: "compatibility with unix" didn't matter in those days. There were many, many OS's, all running on computers so expensive (for whichever micro/mini/mainframe segment) that most people didn't expect to replace them, ever. cpm vms tops10 tops20 unix multics rsx11 mvs os/360 gcos apple dos etc etc etc.