Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!njin!princeton!twg.com!dwh
From: dwh@twg.com (Dave W. Hamaker)
Newsgroups: comp.dcom.modems
Subject: Re: Using High Speed Modems
Message-ID: <8998@gollum.twg.com>
Date: 30 May 91 21:44:59 GMT
References: <28675@uflorida.cis.ufl.EDU> <6536@vela.acs.oakland.edu> <3958.283bf0b4@hayes.uucp>
Distribution: na
Organization: The Wollongong Group, Palo Alto, CA
Lines: 25

tnixon@hayes.uucp writes:

>In article <6536@vela.acs.oakland.edu>,
>rdthomps@vela.acs.oakland.edu (Robert D. Thompson) writes: 

>> 	Do modems with V.42 compression cause compressed files (e.g.
>> 	PKZIP, LHARC, etc...) to become effectively larger when
>> 	transferred?  In other words, is there negative compression
>> 	when transferring a compressed file via V.42?

>Any compression scheme will expand data that does not have enough 
>redundancy in it, simply because of the overhead required to pass 
>the data through the encoding scheme.  This can happen if the data 
>is pre-compressed, or simply random by nature (e.g., object code).

>....

This is really an aside, but I'd like to point out that object code is
not random.  We tend to think of it in those terms simply because it is
not designed for direct consumption by people; we just imagine it looks
like random jiberish when we make a mental picture of object code as
byte stream.  In my experience, object code compresses quite well.

-Dave Hamaker
dwh@twg.com