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From: byron@archone.tamu.edu (Byron Rakitzis)
Newsgroups: comp.compression
Subject: Re: DDJ compression competition FLAME
Message-ID: <14294@helios.TAMU.EDU>
Date: 8 Apr 91 04:30:39 GMT
References: <1991Apr8.160133.22070@kcbbs.gen.nz>
Sender: usenet@helios.TAMU.EDU
Organization: College of Architecture, Texas A&M University.
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In article <1991Apr8.160133.22070@kcbbs.gen.nz> Peter_Gutmann@kcbbs.gen.nz (Peter Gutmann) writes:
>#flame on  
>  A few days ago I finally managed to get hold of the Feb'91 DDJ.  There were 
>two things about the compression competition that disturbed me:  
>  
>1. The test data is known in advance.  It is thus possible to write a  
>compression program which will compress it arbitrarily well.  Since the output
>of the program is known in advance, no information is being transmitted, thus 
>the data can be compressed to 0 bytes.  In theory I could submit a program  
>which, for compression, creates a 0 output byte file; for decompression, it  
>copies data from a static internal buffer to the output file as fast as it can

Just a comment here: last year, the Princeton CS department sponsored just
such a competition, i.e., the assignment was to compress and uncompress
a given dictionary. The competition was graded according to the sum of
(1) the compressed dictionary file, and (2) the size of the decompressing
executable. It was quite possible, and some even found it desirable to set
(1) to zero and to simply submit a huge program which produced a given output.

Not to say that this is a valid way of producing general-purpose compression
algorithms (I think this is the point of the competition in DDJ? I can't really
infer this from your article, and I have not read the journal myself) but it
does have its place.