achieving 19200 baud on the UNIX PC

Alex S. Crain alex at umbc3.UMD.EDU
Sun Jul 3 06:54:01 AEST 1988


In article <187 at gizzmo.UUCP> Kdavid at gizzmo.UUCP (David Solan) writes:
>-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
>
>It was suggested by Bob Ames that you could achieve a baud
>rate of 19200 by replacing getty in /etc/inittab with uugetty.  Though

>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.

	Sorry, Its even more fundimental thatn that. A vt100 can't scroll
at 19Kb, period. It can talk at 19Kb through the wonders of XON/XOFF flow
control. That means that the terminal will accept input at 19K until its
internal buffers fill up, and then send XOFF (^s) to the host which 
instructs the host tostop sending input until an XON (^q) is sent, after the 
terminal has dispersed its buffered data.

	The window driver can't talk at 9600 baud either. 

	19Kb terminal output is only really useful over terminal networks,
because it enables the host to send data in spurts, and terminals spend
less time waiting for other terminals. 

	I would be interested to see if two 3b1's could sustain 19Kb (or
higher) file transfers (uucp or whatever). Anybody ever tried?




	-- 
					:alex.

nerwin!alex at umbc3.umd.edu
alex at umbc3.umd.edu



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