There were three window systems that I know of that ran on the various
incarnations of that machine. The first, mpx, was very basic. The second,
mux, allowed editing of text on the screen and had some interesting
properties, such as "hold mode", which stopped all reads to the host until
hold mode was cancelled. This allowed one to use the terminal window as a
general text editor for any application, and was obviously an influence on
various followons. It also didn't satisfy any read to the host until you
hit return, so all hold mode did was make its basic one-line operation
multiline, but it felt liberating and was used constantly for writing mail
messages and so on.

Both these systems depended (eventually) on new v8 stuff like streams and
select, so they didn't work on System 3 etc. USG did a thing for themselves
called layers, which was more like mpx than mux.

-rob


On Tue, Feb 11, 2020 at 8:33 PM <arnold@skeeve.com> wrote:

> Rob Pike <robpike@gmail.com> wrote:
>
> > Readline and job control were less compelling when you had multiple
> command
> > windows of editable typescript, which we all had with the Blit.
>
> Understandable. But the 99.9999% of us not in 1127 only had glass ttys.
>
> I did have a DMD 5620 for a while (which I loved), but I don't recall
> that it had editiable typescripts.  I thought that that came in
> with 8-1/2 in Plan 9?
>
> Thanks,
>
> Arnold
>