Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hp-sdd!apollo!weber_w
From: weber_w@apollo.HP.COM (Walt Weber)
Newsgroups: comp.sys.apollo
Subject: Re: getty problem at sr10.1
Message-ID: <46d9cf80.20b6d@apollo.HP.COM>
Date: 15 Nov 89 13:01:00 GMT
References: <8911111819.AA02201@civilgate.ce.uiuc.edu>
Sender: root@apollo.HP.COM
Reply-To: weber_w@apollo.COM (Walt Weber)
Organization: Hewlett Packard NARC @ Apollo Systems Division
Lines: 44

In article <8911111819.AA02201@civilgate.ce.uiuc.edu> lray@CIVILGATE.CE.UIUC.EDU (Leland Ray) writes:
>
>It all started when I moved the node to SR10.1.
>
>Upon checking the node, I noticed that there was no free disk space, and both
>gettys were in an infinite loop. Rebooting the node recovered 70M in disk space.
>
>It seems that the serial lines, for as yet unknown reasons, were flooding the
> line with large numbers of garbage characters. Most of them were ^? 
> (Ascii 0xff) with a few o's (Ascii 0x7f) thrown in for good measure.
>
Leland -

First of all, it looks like you addressed the symptoms of the problem with your
mods to getty (like you said, good thing you were "blessed with the source").

It sure looks like the underlying CAUSE is yet to be addressed, however, since
you are still getting what appears to be line noise on the serial port.  The
behavior is similar to that observed when a modem is attached for dial-out, but
is not configured to eliminate result codes (like any Hayes compatible, for
example).  Thus getty sends a prompt to the modem, the modem sends back either
OK or ERROR (which getty interprets as a login user name & exec's login), login
prompts for a password and exits on the timeout signal, which respawns getty,
and the cycle repeats.

Finding and eliminating the cause of the line noise (0xff & 0x7f are some of
the more common "noise indicators") should enable you to use the standard
getty without problem.  This is in no way meant to indicate that your getty is
"inferior", it's just less hassle if you don't have to install local mods on
every release, right?

I would also expect that the line is noisy when under use by the PC operator.
If she isn't seeing any noise, I would **suspect** that the rs232 cable is 
being disconnected from the PC and thus acting as an antenna to induce signals
on the cable - this is a very common scenario in timesharing mini systems, and
can generally be addressed by installing an AB switch at the PC end (I think).

Good luck in killing the cause, once you find it.

...walt...

Walt Weber               Hewlett Packard NARC @ Apollo Systems Division
(508) 256-6600 x8315     People's Republic of Massachusetts
-The views expressed herein are personal, and not binding on ANYONE-