3B1 vs. 7300, uucp/mail Fight, Round One

[Michael "Ford" Ditto]

In article <9377 at cup.portal.com> thad at cup.portal.com writes:
>Has anyone succeeded in connecting two UNIX-PCs via a single serial port on
>each system and having bi-directional uucp and mail function between them?

Yup.  I've seen several systems working this way.

>The "fight" occurs when both systems have their (respective) serial port
>configured as "CALLER and HOST.

Yes, it's called "babbling gettys", and it happens to any Unix systems
when configured this way.

>When one system is configured as "CALLER" and the other as "HOST", there is
>no conflict, but mail and uucp traffic only flows from the CALLER to the
>HOST; uucp or mail on the HOST remains queued forever.

This is not quite true.  In that setup, communication will flow in both
directions, but a "conversation" can be initiated only by the "CALLER"
system.  This means that mail from the HOST will be queued until the
next time the CALLER calls.

You can make the CALLER machine poll the HOST periodically using cron;
causing a poll every half-hour or so is usually quite acceptable for
directly connected machines.

crontab entry:
	08 * * * * /bin/su uucpadm -c "/usr/lib/uucp/uudemon.hr > /dev/null"

/usr/lib/uucp/uudemon.hr entry:
	rm -f /usr/spool/uucp/STST.${HOST}
	uucico -r1 -s${HOST}

Another possibility is to use a special version of "getty" which doesn't
"babble" (usually these work by not doing any output until they see
something that looks like a login attempt).  Several of these exist,
usually called "uugetty".
-- 
					-=] Ford [=-

"The number of Unix installations	(In Real Life:  Mike Ditto)
has grown to 10, with more expected."	ford at kenobi.cts.com
- The Unix Programmer's Manual,		...!sdcsvax!crash!elgar!ford
  2nd Edition, June, 1972.		ditto at cbmvax.commodore.com