From: utzoo!decvax!harpo!npoiv!npois!houxm!ihnp4!ixn5c!inuxc!pur-ee!uiucdcs!emrath
Newsgroups: net.unix-wizards
Title: Re: bug fixes to terminal handler of 4.1 - (nf)
Article-I.D.: uiucdcs.1276
Posted: Mon Dec 27 10:53:47 1982
Received: Fri Dec 31 06:41:31 1982

#R:linus:-75900:uiucdcs:13700012:000:917
uiucdcs!emrath    Dec 23 18:37:00 1982

I'm a little confused - how can a machine refuse to accept 2 stop characters?
I assume you mean that the 2nd one causes the machine to resume output.
In this case, changing unix is like treating the symptom rather than the
disease.
(We had a pathological driver like that here on a CYBER and we got
them to change it fast)
What if the first ^s gets garbled or lost or something, and you keep
receiving data? You have no choice but to send another ^s with no way of
knowing which position the remote machine's "toggle" is in.
It is clear that the flow control protocol should be to ALWAYS stop when
a ^S (stop char) is received. Whether only a ^Q or anything BUT ^S should
resume transmission is open to further debate.
^S as a toggle is a big mistake (which unix doesn't make),
and I recommend not changing unix to compensate for external systems
that are inherently wrong. If you must, make it a non-default option.