Multiplexed Special Devices

[Guy Harris]

 >IBM has them in AIX v3.1 as multiplexed character devices.  each
 >open returns a different channel.  Thus, the PTY device driver is
 >a multiplexed character device.  When you want a PTY pair you open
 >/dev/pts and see what you got.  Then you open the /dev/ptc that
 >matches, and you have a PTY all to yourself.

That's a clone device, not a V7-style multiplexed character device; the
latter is what was being asked about.