csh and shell layers request/question

[Doug Gwyn]

In article <5366 at alice.uUCp> sgt at alice.UucP (Steve Tell) writes:
>BTW, has anyone written somthing like shl for BSD systems (using
>pty's) or Version-8 (using pt's & line disciplines, etc)?
>It shouldn't be too difficult with these features available.
>Shl goes to lots of trouble, there's a special SYS-V device
>driver that does the multiplexing. (called an sxt).

There is a program called "mpx" in use for Teletype 5620 DMDs.
It does more than is needed for simple "shl" emulation, however,
since it operates in parallel with an operating system in the
5620, using suitable packet and control protocols.  Once could
take the existing "mpx" source and remove a lot of 5620-specific
stuff from it to obtain an "shl"-like multiplexer.  I don't know
anyone who has done that; what would be the point of it when you
have Berkeley-style ^Z job control available for dumb terminals?