Info needed on pseudo TTYs in SysV

[Doug Gwyn <gwyn>]

> I have a stream of data coming in on a standard TTY port.  This stream 
> consists of several multiplexed TTY sessions.  I need to demux this stream 
> (not a problem), and feed the demuxed outputs to several pseudo TTYs (a
> problem).  On the other side, I need to take the streams from the pseudo
> TTYs, multiplex them into a single stream, and send it out the standard
> TTY.  I need all the standard UNIX utilities to run from a pseudo TTY.

This is what the "sxt" pseudo-devices are designed for
(Release 2.0).  There are no real ptys on any UNIX System
V that I have seen, although they would be a natural for
stream I/O-based releases such as are expected someday..

Note that your situation is similar to that of the DMD
(aka Blit); AT&T provides an "xt" driver with the DMD
software.  However, the "xt" driver is DMD-specific and
therefore probably not suitable without major hacking.