Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!texbell!vector!netsys!faatcrl!jimb
From: jimb@faatcrl.UUCP (Jim Burwell)
Newsgroups: comp.mail.uucp
Subject: Re: New UUCP Protocol (was: Re: Zmodem added to UUCP)
Message-ID: <1029@faatcrl.UUCP>
Date: 7 Oct 89 05:32:20 GMT
References: <1024@faatcrl.UUCP> <710@lakart.UUCP>
Organization: FAA Technical Center, Atlantic City NJ
Lines: 55

dg@lakart.UUCP (David Goodenough) writes:

>jimb@faatcrl.UUCP (Jim Burwell) sez:
>> aris@tabbs.UUCP (Aris Stathakis) writes:
>>>The 'g' protocol is a bit outdated.  We need something NEW and better.
>>>Some ideas i had -
>> 
>> The 'g' protocol is a bit outdated.  But it's not as bad as one might think.
>> There is a bit of windowing involved, which makes 'g' much faster than 
>> other protocols which also require handshakes after every block

>Now, let's see. 2400 BPS * 64 data characters per block / 70 actual characters
>means you can crank along at about 219 CPS, or 91.4 % of available
>bandwith. A good Ymodem / Xmodem 1K can get up to the same neck of the woods:
>I usually hit about 214 - 216 CPS on an Xmodem 1K transfer.

Yes.  I know the short blocks waste a lot of bandwith, but from watching modem
lights, etc, it sure seems to me like there is some windowing going on.  I'm
not sure, but it seems that 'g' continues to send blocks before it gets acked.
Either that, or some uucicos spoof it by sending acks before chcking the block
or something.  I guess I'll have to dig through some uucico source..

>What _WOULD_ be worth doing, and uucico has the ability, is to increase the
>packet size above that #@%*! 64 byte limit. 256 byte packets would mean 262
>actual:

[stats deleted...]

yes.  increasing the packet size would really help, but it seems like a 
band-aid fix.  I still want zmodem!  (or some other streaming protocol..but
why invent a new one ?)

>Also the g protocol has the ability to run bidirectionally, what is needed is
>to adjust the _FILE_ level section to take advantage of this. Maybe, just
>maybe, one day I'll do this. Of course, you wouldn't want to do this with a
>pair of TB's running PEP - it'd get really messy :-) Or would it - with the

bidirectional transfers would definitely not gain you much with a PEP
connection.. I think the back channel is only 300 baud or so.  I'd be happy 
with Zmodem for now :-).

-- 
+------------------------------------------------+--------------------------+
|          James S. Burwell                      |                          |
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