Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!wugate!uunet!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.mail.uucp
Subject: Re: New UUCP Protocol (was: Re: Zmodem added to UUCP)
Message-ID: <975@crdos1.crd.ge.COM>
Date: 10 Oct 89 17:52:16 GMT
References: <1024@faatcrl.UUCP> <710@lakart.UUCP> <1029@faatcrl.UUCP> <688.252e37c2@simpact.com>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: GE Corp R&D Center
Lines: 39

In article <688.252e37c2@simpact.com>, jeh@simpact.com writes:
|  uucp 'g' definitely "streams" (or, in more conventional parlance, does 
|  windowing with transmit windowsize > 1; 3 is typical and is more than
|  sufficient to keep the transmitter transmitting continuously), and, no,

  This depends on your situation, when I installed a new version of UNIX
I forgot to set the windows to seven, and the throughput was down around
200cps. Going to seven brought it back to 220. This makes even more
diference in MNP mode. Don't ask why, I just read the xferstats.

|  the other end doesn't spoof.  (The Telebit Trailblazer in uucp spoofing
|  mode *does* spoof, but that's another issue.)  There are a few implementations
|  (e.g. the gnuucp versino which was the basis for DECUS (VMS) uucp) which
|  don't do windowing but these are the exception.  

  And the performance is pretty poor, too.

|  
|  An increased packetsize will produce, at best, a marginal improvement.  
|  We typically see at least 215 char/sec throughput with 64-byte packets.
|  Allowing 512-byte packets increases the theoretical max from 219.4 char/sec
|  to 237.2, a whopping 8% increase.  Not a big deal.  And, as someone else 
|  said, increasing the packetsize increases the expense of error recovery.  

  I agree with your technical comments, but 8% can be important if (a)
you pay out of your own pocket, or (b) you are talking a large phone
bill. Some sites have bills of $6000+/month, and they could justify a
few days of someone's time if it were that simple. Note, I don't say it
necessarily is, and faster modems seem to be more cost effective with
spoofing, but don't think the 8% would be unimportant to everyone.


	[ much good explanation of NAK frequency tradeoffs ]

-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon