Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!ubc-cs!eric!zaphod.mpr.ca!parker
From: parker@zaphod.mpr.ca (Ross Parker)
Newsgroups: comp.unix.questions
Subject: XON/XOFF buffer control
Message-ID: <1928@eric.mpr.ca>
Date: 28 Nov 89 23:41:31 GMT
Sender: news@eric.mpr.ca
Reply-To: parker@zaphod.mpr.ca (Ross Parker)
Organization: Microtel Pacific Research Ltd. (MPR)
Lines: 20


Hi...

	Does anyone know how flow control is handled in the
tty driver in the case where an external device is not able
to halt output immediately upon receiving an XOFF, i.e. it
must send 'a few' characters after getting the XOFF?

	Is there some kind of threshold involved such that the
XOFF goes out when the input buffer still has room? How much
room is left in the input buffer?

	In particular, I need to know this for LAT ttys under
ULTRIX 3.0 and 3.1, but any generic info would be useful.

Thanks,


Ross Parker				parker@mpre.mpr.ca
(604)293-5495				uunet!ubc-cs!mpre!parker