I first used Unix on a pdp-11/70 in 1981, first year at university.  My professor stopped by the computing center to see how his students were doing - super nice of him and a perk to pre-PC times! - and was showing me something or other regarding Unix.  I had only used ed to that point and seeing him fire up vi was practically sci-fi to me.  He showed me a few commands and vowed me to secrecy for fear if all students started using it, it would bring the 11/70 to its knees.  Were multiple vi sessions really such a potential burden to the machine?  I wouldn't think so with the slow nature of human i/o, yet there certainly were times when the pdp-11/70 crashed as project due dates loomed closer and closer!

Also, I very much enjoy this list.  As an EE I use Unix-like OSes as a tool rather being a builder of the tool like many here.  So I don't have the deep background to contribute to the collective history, but I'm on the sidelines enjoying the show.  As a brief tie-in to the editor comparisons, I do a lot of DSP work for RF systems these days.  Python makes it quick and easy to try new math, but has a maddening requirement that indentation be strictly tabs or strictly spaces.  Text window pasting into a tab indented python file wreaks havoc.  vim yank/put between split windows retains the type of white space and lets me use my vi muscle memory.

Happy 2020,

Mike Markowski