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Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!umd5!mimsy!oddjob!gargoyle!ihnp4!homxb!mtuxo!mtune!codas!killer!jfh
From: jfh@killer.UUCP (The Beach Bum)
Newsgroups: comp.unix.xenix,comp.unix.questions
Subject: Re: moby bignum tty accesses in /usr/adm/wtmp
Message-ID: <1830@killer.UUCP>
Date: Thu, 15-Oct-87 17:58:31 EDT
Article-I.D.: killer.1830
Posted: Thu Oct 15 17:58:31 1987
Date-Received: Sat, 17-Oct-87 17:50:30 EDT
References: <1134@gilsys.UUCP> <1616@bloom-beacon.MIT.EDU>
Organization: Big "D" Home for Wayward Hackers
Lines: 32
Keywords: wtmp, acctcom, what the hell?, HELP
Summary: $0.02 on the problem ...
Xref: mnetor comp.unix.xenix:973 comp.unix.questions:4538

In article <1616@bloom-beacon.MIT.EDU>, wolfgang@mgm.mit.edu (Wolfgang Rupprecht) writes:
> 
> In article <1134@gilsys.UUCP> mc68020@gilsys.UUCP (Thomas J Keller) writes:
> >Problem:  /usr/adm/wtpm growing at alarming rate (>500K/day).  Manual
> >	  checking revealed a *LARGE* number (on the order of 9000) accesses
> >	  to /dev/tty02 beginning at 03:00 and continuing through 04:29,
> >	  at the rate of approximately 95-120 accesses per MINUTE!
> 
> Why not solve the mystery and put a terminal on the line and watch 
> the chars fly? (just connect up the terminal's rs232 signal-ground 
> and recieve lines to the tty as a monitor.)

A problem I saw once on an unconnected line was that character transmitted
by the system were being recieved back, possibly changed alittle ;-), even
though nothing was one the line.  Hooking up a terminal made the problem go
away - BUT - the guy on the other end of the wire had an AB switch and didn't
like having to use only one system.

The Fix?  I added a 10K resistor between RxD and ground on the System end of
the cable.  Didn't do anything while he was using the line, and when he
wasn't, the resistor pulled the line down to ground rather than letting it
float.

The Moral? Engineers (he was an engineer) have their heads up their butts
too much of the time ... (he also happened to have wired the systems ;-)

- John.
-- 
John F. Haugh II		HECI Exploration Co. Inc.
UUCP:	...!ihnp4!killer!jfh	11910 Greenville Ave, Suite 600
"Don't Have an Oil Well?"	Dallas, TX. 75243
" ... Then Buy One!"		(214) 231-0993