Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-winken!uunet!tektronix!sequent!mntgfx!gssc!jimd
From: jimd@gssc.UUCP (James DePorter)
Newsgroups: comp.sys.sequent
Subject: Re: Systech MTI-1600 tty problems.
Keywords: sequent systech terminal
Message-ID: <5911@gssc.UUCP>
Date: 13 Apr 89 17:50:09 GMT
References: <834@htsa.uucp>
Reply-To: jimd@gssc.UUCP (James DePorter)
Organization: Graphic Software Systems, Beaverton Or
Lines: 51

In article <834@htsa.uucp> jand@htsa.uucp (Jan Derriks) writes:
>Who can help me with the following problem:
>
>Sometimes, when a terminal is switched off and on ca. 25 
>times (in 2 weeks or so) the /dev/ttyxx line 'hangs'. 
>Nothing else but a reboot of the system helps.
>An echo >/dev/ttyxx appears on the screen, but I cannot
>read /dev/ttyxx at all.
>Fortunately not all tty lines have this problem.
>

I have had the same problem, I have f100's hooked to our B8. Two things
I noticed is that it happened more with newer users and most of the emacs
users. I found that when the emacs users rsh to our vax some of the
control codes change for them i.e. ^s would hang them (of course) 
and they wouldn't be paying attention to the flow control and try to
kill everything they were doing to get back working on that port.
I have found if you can send the ^q before all of the processes are
killed you have better than 90% chance of recovering. The reason I
bring up f100's is that they sometimes put garbage onto the line and
can hang the terminal. Switching terms off and on can leave the port
in the wrong flow control state also. The worst problem is not being
able to kill csh as root when someone has flow control stopped.

>
>Big question is: how can I 'reset' the /dev/tty line like a 
>system reboot does, without actually having to do a complete reboot ?
>Anybody knows this problem and has an answer: post it or please
>send to (uucp)..hp4nl!htsa!jand.  Thanks.
>

I haven't found a way once the port is gone. Usually I find an unused
port until I can reboot at night (less impact on the local community
(-8  ).


>Jan Derriks                   |  AHA-TMF (H.T.S. 'Amsterdam')
>email: hp4nl!htsa!jand        |  Europaboulevard 23
>phone: +31 20423827           |  1079 PC Amsterdam,  The Netherlands


jimd
tektronix!sequent!gssc!jimd

Not a spokesperson for Sequent, just a satisfied user. 
Now where is that check for the Symmetry upgrade? I had it here somewhere....

-- 
				"When in doubt, logout"

and now a fortune: