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From: gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>)
Newsgroups: net.unix-wizards
Subject: Re: TTY Inquiry
Message-ID: <2117@brl-tgr.ARPA>
Date: Mon, 14-Oct-85 07:37:19 EDT
Article-I.D.: brl-tgr.2117
Posted: Mon Oct 14 07:37:19 1985
Date-Received: Tue, 15-Oct-85 07:38:43 EDT
References: <482@scirtp.UUCP> <2888@sun.uucp>
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Organization: Ballistic Research Lab
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> > Currently under Bell UNIX, data communications for ttys are
> > uni-directional.  For example, once a port is conditioned to send out
> > data, it can not readily receive data.
> 
> What?  When I log into a UNIX system, I can type at it at the same time it's
> typing at me.  What do you mean by "conditioned to send out data"?  You
> can't have one process blocked on a "read" on that port and doing a "write"
> on the port at the same time on any current UNIX.  Programs like "cu"
> usually work by having two processes, one doing the reads and one doing the
> writes.

I couldn't figure this out either.  Finally I decided they must be
talking about setting different terminal modes (stty) for the
outgoing and incoming data channels.  If not, I wish they'd explain.