Path: utzoo!attcan!telly!robohack!hybrid!becker!bdb
From: bdb@becker.UUCP (Bruce Becker)
Newsgroups: comp.sys.amiga
Subject: Re: Modem Transfer Throughput (was Re: Dnet)
Keywords: Dnet, Telebit Trailblazer
Message-ID: <5659@becker.UUCP>
Date: 8 Mar 90 23:29:00 GMT
References: <25358@swrinde.nde.swri.edu> <1990Mar7.000117.6984@ncsuvx.ncsu.edu> <23299@usc.edu>
Reply-To: bdb@becker.UUCP (Bruce Becker)
Distribution: na
Organization: G. T. S., Toronto, Ontario
Lines: 33

In article <23299@usc.edu> papa@pollux.usc.edu (Marco Papa) writes:
|[...]
|If you "pre-compress" the program (whith compress, zoo, arc, squeeze) before
|sending the file, you WILL LIKELY *decrease* the transmission rate IF you've
|set up your modem to do compression itself. So best performance with modems
|that support compression can be achieved either by:
|
|a) transfer the original file "uncompressed", with your modem(s) compression
|   turned ON.
|
|b) compress the file at the origination site and turn OFF your modem(s) 
|   compression.
|
|Most modem manuals will suggest you to do a).

	It seems that b). is the most advantageous
	however.

	Ususally the bottleneck is the time it takes
	to transfer data thru the serial port.
	for a). twice the amount of data (on average)
	goes through the port than for b). It
	usually takes a similar amount of time for
	the modem to compress as it does the host,
	so often there's no advantage to modem-based
	compression.

Cheers,
-- 
  (__)	 Bruce Becker	Toronto, Ontario
w \@@/	 Internet: bdb@becker.UUCP, bruce@gpu.utcs.toronto.edu
 `/v/-e	 UUCP: ...!uunet!mnetor!becker!bdb
_/  \_	 "They never tell you shit like this in high school!" - J. R. Dobbs