From: utzoo!henry
Newsgroups: net.unix-wizards
Title: Re: Dialing in and out (line turn around) 
Article-I.D.: utzoo.2489
Posted: Thu Sep 23 19:58:53 1982
Received: Thu Sep 23 19:58:53 1982

The scheme that Bob Van Valzah discusses works fine.  We have been
running an essentially-identical setup, invented independently earlier
this year, for several months.  There is one thing you must watch,
however:  having two /dev entries sharing a tty structure and a
physical device can lead to problems with initializing and finalizing
the structure and the line.  Not unsolvable, but it needs to be thought
through carefully.  Also, the V7 tty.c does a few unfriendly things
here and there like zeroing the tty flags field on close -- not good
if you have another process waiting for the device!  Easy to work
around but you must be aware of the problem.

						Henry Spencer
						U of Toronto