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From: moore@UTKCS2.CS.UTK.EDU
Newsgroups: comp.unix.wizards
Subject: DCA multiplexer problems
Message-ID: <10511@brl-adm.ARPA>
Date: Mon, 23-Nov-87 19:36:51 EST
Article-I.D.: brl-adm.10511
Posted: Mon Nov 23 19:36:51 1987
Date-Received: Thu, 26-Nov-87 05:39:15 EST
Sender: news@brl-adm.ARPA
Lines: 26

We have an VAX 8200 running Ultrix.  One of the peripherals on this system
is a Unibus card which is connected to a DCA terminal multiplexer.
To the VAX, it looks like a (I think) DMF32.

This system has a strange bug which exhibits the following symptoms:

- Whenever a user types ^C or ^O to stop the output of a program, the
  user's tty hangs.  The only way out is to disconnect and log back in.

- ^Z, however, works fine.

- This only happens on the lines assigned to the DCA.

- The only place where I have observed the symptom is when the tty is in
  normal mode (not raw, not cbreak).

I believe the problem to be that the DCA is not quite emulating the DMF32,
but I believe the best solution to be some sort of patch to the device
driver.  (We do have kernel sources.)

Has anyone seen this before?  Can anyone offer a suggestion or fix?

Keith Moore
UT Computer Science Dept.	Internet: moore@utkcs2.cs.utk.edu
107 Ayres Hall, UT Campus	CSnet: moore@tennessee
Knoxville Tennessee		BITNET: moore@utkcs1