Article View: comp.bugs.4bsd
Article #1406script problem
From: Bill Stapleton
Date: Tue, 19 Dec 1989 21:32
Date: Tue, 19 Dec 1989 21:32
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1755 bytes
[I posted this to comp.unix.wizards and got no response, so...]
I've been looking into a problem we have with the script program garbaging
output to the terminal. I haven't found a newer version, fix, or mention of
this problem, so here goes. This is with BSD 4.3-tahoe and script 5.6:
The problem seems to stem from script running in RAW mode, expecting everything
else to take care of the flow-control. Unfortunately, the response to XOFF is
then too slow, and a slow terminal is over-run, producing various unusable
displays. I note that other programs, notably rlogin, use the TIOCPKT feature
of the pty to figure out when RAW mode is neccesary, running CBREAK (with its
own local flow-control) otherwise. Is there a reason that script doesn't do
this? (appologies if I've condensed this down past making any sense)
Does anybody else consider this a real problem? Has anyone fixed it?
(This problem may be reproduced using a "slow" terminal which requires flow-
control to "keep up", running script, then running something that produces
lots of output quickly (ls, etc); Alternately, simply notice how slow the
response to XOFF is while running through script)
--
Bill Stapleton
wls@csd4.csd.uwm.edu
uwmcsd4!wls
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Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uwm.edu!csd4.csd.uwm.edu!wls From: wls@csd4.csd.uwm.edu (Bill Stapleton) Newsgroups: comp.bugs.4bsd Subject: script problem Summary: Is script broken? Is there a fix? Keywords: script, pty, ^S/^Q, RAW/CBREAK modes, TIOCPKT Message-ID: <1571@uwm.edu> Date: 19 Dec 89 21:32:32 GMT Sender: news@uwm.edu Reply-To: wls@csd4.csd.uwm.edu (Bill Stapleton) Organization: Computing Services, U of Wisc-Milwaukee Lines: 25