Path: utzoo!mnetor!uunet!edsews!roberts
From: roberts@edsews.EDS.COM (Ted Roberts)
Newsgroups: comp.dcom.modems
Subject: Re: hayes 9600 vs. trailblazer
Message-ID: <494@edsews.EDS.COM>
Date: 12 Apr 88 16:01:33 GMT
References: <8804110136.AA16978@ucbvax.Berkeley.EDU> <15612@onfcanim.UUCP>
Organization: EDS - Bloomfield Hills, MI
Lines: 25
Summary: how does doing compression on the host save CPU time.

In article <15612@onfcanim.UUCP>, dave@onfcanim.UUCP (Dave Martindale) writes:
> 
> (I know that some modems, including the Trailblazer, can get higher
> effective throughput by compression.  But news is usually already
> compressed (it actually saves host CPU time to do the compression
> on the host) and doing compression in the modem is counterproductive).
> 
I realize that news is normally compressed by the system before transmission
partly due to the modems that don't do data compression in the hardware.
However, I'm curious if in a this is actually the best method for the
Trailblazer.  Is the modified Lempel-Ziv data compression algorithm used
by the news better than the type used by the Trailblazer?  What algorithm
is used by the TB?

If the data compression used by the news is better, though, there are still
other types of data to send that are not compressed.  For this type of data
(mail comes to mind) I would disagree that doing compression in the modem
is counterproductive.  This is by no means a flame, I personally don't know
much about the data compression techniques used and would like to learn a
bit more.

-- 
Ted Roberts                         |  My opinions are not necessarily those
EDS Technical Services Division     |  of my employer.  Does that mean I'm
UUCP: roberts@edsews.EDS.COM        |  wrong?