Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!cs.utexas.edu!rutgers!ub!dsinc!syd
From: syd@DSI.COM (Syd Weinstein)
Newsgroups: comp.mail.uucp
Subject: Re: How efficient/fast is uucp?
Message-ID: <1990Aug25.144323.10811@DSI.COM>
Date: 25 Aug 90 14:43:23 GMT
References: <8464@pitt.UUCP> <1556.26d282ea@dcs.simpact.com> <1990Aug24.152938.7413@chinet.chi.il.us>
Reply-To: syd@DSI.COM
Organization: Datacomp Systems, Inc.  Huntingdon Valley, PA
Lines: 48


>>Technically:  There is a "protocol negotiation" sequence in the uucp startup, 
>>so it is possible to have a uucico that supports both the standard 'g'
>>protocol and, say, zmodem, and which will use the appropriate protocol for
>>each host to which it connects.  
What everyone is forgetting here, is that the protocol is only used
for sending the file itself.  As was stated, there is still the undrelying
problem of sending small files, such as mail messages.

uucico is split into two functions, one find the requests to send across,
and the other actually does the data transfer.  Its the data transfer
that uses the protocol negotiated.

Thus for a mail send, uucico doesn't know its mail.  It just sees a request
so send 2 files, a 'command file' which is the remote execution of the
rmail command, and the 'data file'.  Both are just a simple file
transfer request to uucico.  Thus there is still the time required to
send these small files that will not be helped by changing the protocol.

A new protocol will only handle the actual sending of a single request
itself.  Talking about zmodem's restart ability is useless, as uucico
will retransmit the entire fill, (again using zmodem protocol if that
is the negotiation).  Yes, the newest HDB from AT&T can restart a file
in the middle, but older ones cannot, and even with Zmodem, they won't
even realize they need to.

Zmodem, as viewed by itself, is a complete transfer system, so it knows
what to do.  The protocol is only a small section of uucico, and must
be viewed in that context.

If you are a mail site, and sending lots of small messages for mail,
then you can improve your throughput by switching to a different
mail protocol, such as BSMTP, still sent via uucp, instead of rmail.

If its news, then selecting correct batch sized will allow for restarts
effectively.

If its a packet link, then just a protocol with a larger window and
selective reject would be needed.  Again, its only the transfer of
a single file that can be improved by changing the 'protocol' module
within uucico.  You would need a whole different concept as a file
transfer device to improve more than that, and then it wouldn't 
be uucico.
-- 
=====================================================================
Sydney S. Weinstein, CDP, CCP                   Elm Coordinator
Datacomp Systems, Inc.                          Voice: (215) 947-9900
syd@DSI.COM or dsinc!syd                        FAX:   (215) 938-0235