Path: utzoo!utgpu!water!watmath!uunet!labrea!agate!ucbvax!ucsd!ucsdhub!cuuxun!cuuxb!att!ihnp4!ihlpl!ihchk!ihtlt!ethos!gizzmo!Kdavid
From: Kdavid@gizzmo.UUCP (David Solan)
Newsgroups: unix-pc.general
Subject: achieving 19200 baud on the UNIX PC
Keywords: 19200 baud console remote terminal
Message-ID: <187@gizzmo.UUCP>
Date: 1 Jul 88 03:06:35 GMT
Lines: 58

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It was suggested by Bob Ames that you could achieve a baud
rate of 19200 by replacing getty in /etc/inittab with uugetty.  Though
I was successful in getting the following to work with the console
screen:

vid:2:respawn:/usr/lib/uucp/uugetty -t60 window 19200

and, though I was successful in getting the following to work with an
RS-232 port (using a VT-100 terminal set to a 19200 rate on Transmit
and Receive):

000:2:respawn:/usr/lib/uucp/uugetty -r -t60 tty000 19200

neither seemed to have ANY effect whatsoever in speeding up cat(1)'s
to their respective screens, or to speed up very long scrolls in the
vi editor, to take two examples.  I DID check this out by changing the
prompts in /etc/gettydefs, and indeed, the 19200 prompt WAS coming out
in both cases, and I also checked it out by keeping the VT-100 at 9600
while raising the uugetty to 19200, producing pure gibberish on the
screen, but, I repeat, there was no significant change in the rate of
output to the screen at 19200 baud versus 9600 baud!

Obviously, this "19200", if it is real at all, is in SERIAL
CONNECTION with a 9600 baud rate or such somewhere or other in the
internals of the machine, thereby rendering the 19200 rate effectively
null and void.

Curiously, even though the vi editor scroll seems to pause to
catch its breath every 20 lines or so, while the cat(1) command seems
to send its output to the screen in a more continuous flowing manner,
both seemed to put out about the same number of bytes per unit time
for long screen outputs on the UNIX PC or on a remote terminal,
effectively about 8000 baud or so (assuming 9 bits out per byte) --
with the remote doing a little better than the UNIX PC console,
ESPECIALLY for files with short lines and many return carriages.

Is an additional change in /etc/gettydefs needed?  What about
changing the "s4" or "vt-100" entries in /etc/termcap by adding:
:pb#19200: ??  What about changing /unix itself?!  If you have any
ideas, I would be glad to experiment with them on a separate machine I
have available if you are afraid to do so on yours.

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David  Solan
Objective Programming Incorporated
Post Office Box 123
Norwalk,  CT  06856
Voice: (203) 866-6900
attmail: <!dsolan>
USENET: gizzmo!kdavid
-- 
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                                             {codas,u1100a}-----\
David Solan                         rutgers!rochester!pcid!kodak!gizzmo!kdavid
                                       {lazlo,ethos,fthood}-----/