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From: bruce@stride.Stride.COM (Bruce Robertson)
Newsgroups: comp.bugs.sys5
Subject: Re: CLOCAL, or catch-22
Message-ID: <677@stride.Stride.COM>
Date: Tue, 25-Aug-87 13:34:59 EDT
Article-I.D.: stride.677
Posted: Tue Aug 25 13:34:59 1987
Date-Received: Thu, 27-Aug-87 04:03:04 EDT
References: <325@nsta.UUCP> <25073@sun.uucp> <3607@sdcsvax.UCSD.EDU> <169@edm.UUCP> <1382@killer.UUCP>
Reply-To: bruce@stride.stride.com.UUCP (Bruce Robertson)
Organization: MicroSage (formerly Stride Micro), Reno, NV
Lines: 27


What is really needed is a device driver that has two interfaces, one
that totally ignores CD (for hardwired lines and talking to modems in
the outgoing direction), and one that handles CD in the "normal" way
(for dialing in).  There should also be an ioctl on the hardwired
interface to tell it that you now want to pay attention to CD, so that
when you lose your connection to the remote machine you aren't left
talking to the modem, which tends to confuse naive users, and is also
a security hole.  There would also be an interlock, so that both
interfaces could be used at once.  This driver would make all the
modem turnaround programs that are in abundance totally unnecessary.
You simply put a getty on the dialup interface, which blocks waiting
for CD, and then freely use the hardwired interface, which works since
the dialup interface isn't completely open.  Obviously, the dialup
interface needs to avoid waking up the getty if the hardwired
interface causes a CD by calling a remote system.

I have such a driver for the Motorola 68681 DUART, and could be
adapted to other serial chips fairly easily.  I'm willing to post it
if anyone is interested.  We've been using it here for several years,
and there are no problems with it.  It *is* copyrighted by MicroSage
however, so you can't use it to make money.
-- 

	Bruce Robertson
	bruce@stride.Stride.COM
	cbosgd!utah-cs!utah-gr!stride!bruce