DECserver 200 does baud rate inconsistently via Ultrix 4.1

[Ian! D. Allen [CGL]]

Point some Ultrix /dev/ttyXX entry at a LAT port on your DECserver, e.g.

     # lcp -h /dev/tty21:SERVER:PORT_1

then log in to the server (via ccr or another port), set priv mode,
enable remote modification on that PORT_1, and "MONITOR SESSIONS PORT 1".

This is what I get on my Ultrix screen when I play with stty commands:

    # stty > /dev/tty21
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    # stty > /dev/tty21
    speed 9600 baud ; -parity raw nl -echo tandem tabs
    # stty > /dev/tty21
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    # stty > /dev/tty21
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    # stty > /dev/tty21
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    # stty > /dev/tty21
    speed 9600 baud ; -parity raw nl -echo tandem tabs

No consistency on the baud rate.  The LAT port is set to autobaud, and
shows a constant "4800" via the MONITOR command.  For those of you who
don't trust the C shell, here's a /bin/sh version:

    # /bin/sh
    # for x in 1 2 3 4 5 6 7 8 9 ; do
    > /bin/stty >/dev/tty21
    > done
    speed 9600 baud ; -parity raw nl -echo tandem tabs
    speed 9600 baud ; -parity raw nl -echo tandem tabs
    speed 9600 baud ; -parity raw nl -echo tandem tabs
    speed 9600 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 9600 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 9600 baud ; -parity raw nl -echo tandem tabs

What kind of consistency is this?  If you do repeated stty commands on
the already open port, you get reasonable results:

    # /bin/sh
    # for x in 1 2 3 4 5 6 7 8 9 ; do
    > /bin/stty
    > done >/dev/tty21
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs
    speed 4800 baud ; -parity raw nl -echo tandem tabs

I ran this a few times, and a few times the first output line showed
the funny "9600" entry, but the rest were fine.

Looks to me like something in the kernel isn't waiting long enough to
get the baud rate info back from the DECserver.

ULTRIX V4.1 (Rev. 52) DS5400
DECserver 200 Terminal Server V3.0 (BL33) - LAT V5.1
-- 
-IAN! (Ian! D. Allen) idallen at watcgl.uwaterloo.ca idallen at watcgl.waterloo.edu
 [129.97.128.64]  Computer Graphics Lab/University of Waterloo/Ontario/Canada