[Animats]

The ancestor of all those full screen terminal editors is the RAND editor, which was on Unix around 1974.[1] Few people outside the DoD research community saw it, because it wasn't free and only worked on some terminals. Functions were triggered by dedicated function keys, not key combos or a command line, and it was customary to use something with 8 to 10 function keys, such as the HP2645A. You could split the screen, edit two files, and do cut and paste. Way ahead of its time.

[1] https://www.rand.org/content/dam/rand/pubs/reports/2008/R217...

[2] https://terminals-wiki.org/wiki/index.php/HP_2645A

[bakul]

I used the rand editor in early 80s & loved its “infinite” quarter plane model. Dave Yost enhanced it quite a bit and called it the Grand editor. But it was hard to maintain as it relied on K&R C. Eventually I gave up and went back to vi.