On Mon, Mar 13, 2023 at 9:24 AM Clem Cole <clemc@ccc.com> wrote:

FWIW I think Minix for the 8088 may have supported them - be worth checking.  

Minix 1.1 and 1.2 didn't have them. Unsure of later versions since they aren't packaged nicely for quick checking.

Coherent didn't seem to have them, but it's kinda hard to tell for sure without more study.

 

My bet would be to look at ITS, WAITES and Twenex for the origin story. 

 TOPS-20 had a way to attach and detach from a PTY. But they didn't keep the state of the screen... programs did, but not the kernel.

Warner