[comp.unix.wizards] pseudo-tty problems

eichelbe@nadc.arpa (06/09/87)

I am running a VAX 11/780 under 4.3 BSD UNIX.

I am using the telnet command to connect from my computer back into my
computer.  When I do this and am logged on the pseudo-tty port, I lose
characters on output.  It's almost as if there was a handshaking
problem of some sort.

Do pseudo-ttys not understand a control-S sent out by the terminal?  It
seems that the terminal is falling behind.  I'm using a VT100, but I
don't think it's the terminal's fault.

Any ideas regarding what I can do to stop losing characters would be
appreciated.

Thank you.
	Jon Eichelberger
	eichelbe@NADC.ARPA

chris@mimsy.UUCP (Chris Torek) (06/09/87)

In article <7755@brl-adm.ARPA> eichelbe@nadc.arpa (J. Eichelberger) writes:
>... under 4.3 BSD UNIX ... using the telnet command to connect
>from my computer back into my computer.  When I do this and am
>logged on the pseudo-tty port, I lose characters on output. ...
>Do pseudo-ttys not understand a control-S sent out by the terminal?

Telnet sends the control-S right down the connection to the remote
machine.  It has to get all the way through the server and down into
the pty before it can be interpreted as a `stop'.  In the meantime,
other output has flooded your VT100's input buffer.  The sending
stops, but too late.

Rlogin attempts to perform XON/XOFF protocol locally so as to avoid
this.  It does not do a perfect job, but it works much better than
telnet.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
Domain:	chris@mimsy.umd.edu	Path:	seismo!mimsy!chris