Ned,
This really is for the group, not you. It was triggered by a recent
exchange.
The Internet Electronic Mail service really is a set of essentially
independent mail services, such as STMP/822/IP, Unix/uucp, internal
proprietary (DEC, Prime(?), cc:Mail, ...), public proprietary
(MCI Mail, ATT Mail, ...) and so on.
The people who connect together any two heterogeneous parts of this
Internet know that they are running a gateway. That is, they know
that the two nets are separate, in very important and potentially
incompatible ways, and approach the task of interconnection with
due fear and care. (If they don't approach with that attitude, they
soon develop it.)
The 7-bit/8-bit discussions need to be clear that each world is
its own world and that transitions for 7-to-8 or 8-to-7 are email
gateways, just as surely as if the transition were 822-to-X.400.
It could be argued that the transition is the same as going from
ethernet to serial line, which is to say buried at a low enough level
to be a relay, but not a semantic gateway. I think that that view
is logical, but will prove operationally incorrect.
The point behind the above is to encourage a view that connecting the
7/8-bit SMTP worlds will have high overhead and need very explicit
care. I haven't noticed that tone in the current messages.
Dave