Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!cs.utexas.edu!uunet!mcvax!hp4nl!maestro!jand
From: jand@maestro.htsa.aha.nl (Jan Derriks)
Newsgroups: comp.sys.sequent
Subject: Systech tty hangup "fixed".
Keywords: hangup tty systech
Message-ID: <948@maestro.htsa.aha.nl>
Date: 31 May 89 12:08:53 GMT
Organization: AHA-TMF (Technical Institute), Amsterdam, The Netherlands
Lines: 26

A few months ago I posted the following article:

-  ...Sometimes, when a terminal is switched  on 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...

In article <52535@uunet.UU.NET> rick@uunet.UU.NET (Rick Adams) wrote:
-    >..Currently, we have a very serious problem with terminal ports hanging.
-    >This hang means that the Sequent totally ignores data sent from the
-    >terminal. Nothing short of rebooting will clear this hang. ...
-    > ... We have to reboot the system on a daily basis to free stuck ports.

We have found two workarounds to prevent this problem:
1. Never switch off your terminal (adhesive tape across the switch).
2. Don't use the rs232 DTR-DCD signal (connect 8 dtr to 20 dcd at the
   connector on the sequent side).

The disadvantage of 2. is that users will not be logged out when they
turn off their terminal or hang up the modem line.

Still, *if* a tty line hangs only a reboot will help...

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