A Data Compression Resource
Mark Nelson has moved his data compression reference material to a new home at DataCompression.info.
I got very interested in data compression back in my days at Symantec. It started because we wanted to be able to recognize all the magic tags used in compressed files during the raw volume scans we performed on badly crashed disks. Compressed file systems then became all the rage for a while. How many people remember a little company from the San Diego area called Stac, whose product Stacker did this until Microsoft tried to force them out of business with Doublespace in DOS 6 (there was also a lawsuit mostly won by Stac)? Amazingly, the company is still around, although it's now known as Previo. Stacker was eventually ported to the Mac and there were a couple others, TimesTwo (from Golden Triangle) and eDisk (by a company called Alysis Software).
Anyway, somewhere around the time I got interested in compression, I started reading articles by Mark Nelson and have been doing so ever since. His book The Data Compression Book still remains a valuable resource if I need to look up some fuzzy concept (I have the 1992 version from MS&T Books).
An odd story about compression. In 1997 we chose to use the zlib compression library as part of our installation application which used the idea of capsules. The file data in a capsule was an AppleSingle file stream pumped through zlib with some additional meta data added on the fly. Sometime in early 1998 we were backing up lots of raw movie files, most of which were too large to fit on a CD. We were struggling with StuffIt, trying to make the movies small enough and in one case, StuffIt was actually making an 800M movie larger. We tried running it through our capsule process and it worked. We ended up compressing all the raw movies as capsules for archival purposes.
11:09:46 PM 
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