[TUHS] screen editors / machine load

[Noel Chiappa]

    > From: Otto Moerbeek <otto at drijf.net>

    > I believe it was not only vi itself that was causing the load, it was
    > also running many terminals in raw mode that killed performance.

I'm not familiar with the tty driver in late versions of Unix like 4.1 (sic),
but I'm very familiar with the one in V6, and it's not the raw mode _itself_
that caused the load (the code paths in the kernel for cooked and raw aren't
that different), but rather the need to wake up and run a process on every
character that was the real load.

When Bernie Greenberg did EMACS for Multics, he had a similar issue. I recall
reading a document with an extensive discussion of how they dealt with this,
especially when using the system over the ARPANET. IIRC, normal printing
characters were echoed without waking up the process; remotely, when using
the network. If anyone's really interested in this, and can't find it themselves,
I can try looking for it.

	Noel