12/4/2004
power compression

I would like to take this opportunity to promote Power Archiver 9.0.

It may seem strange that I am promoting a proprietary software (albeit shareware), but I just have to because it truly does match and even beats WinZip. Its not that I hate WinZip or anything, I mean I've been using it ever since I switched to Windows 3.1 way back when I was still in junior high. WinZip has served its purpose admirably, albeit at the cost of PkZip's (at the time) main source of income.

And that was how WinZip got its life. Anybody who's been using computers long enough would remember that WinZip was just a graphical frontend for PKWare's PKZip and PKUnZip when it was first released. And then few versions later it built its own internal full-fledged compression engine thus making PKWare's executable unnecesary in Windows. The funny thing is PKWare itself began life by allegedly hijacking a compression algoritm that was generally presumed to be free knowledge in the public domain.

Few outside of the enthusiast PC-user community would remember, but there was a bit of an uproar in the software industry during the early eighties when a company named Unisys patented the LZW compression algorithm (more about compression patents from faqs.org). Back before Unisys patented the algorithm it was generally thought by the general programming community that LZW cannot be patented since the authors disclosed all the technical details of the algorithm to the general public at 1977. But the patent application was granted, and Unisys licensed it to Compuserve for the creation of the GIF format, and then to PKWare to create the ZIP format.

Fortunately the LZW was only a variation of an algorithm. Abraham Lempel and Jacob Ziv disclosed the LZ77 algorithm to the world in 1977. Variations of that algorithm can be found easily by googling LZW or LZ77. Anyway as history goes there was a backlash from the Free Software community to the patent. InfoZip was created, and also GnuZip (its extension is .gz). Other mathematicians tried improving the old algorithm. A result that was popular among the open source community was the BZip2 algorithm (with the extension .bz2).

I had discovered BZip2 while examining my Fedora 2 installation and noticed that for documentation that was both packaged in .zip, .gzip, and .bz2, the .bz2 archive was noticeably smaller while the .zip was significantly bigger. I searched for a utility to create and open bz2 archives, and what I discovered was the already mentioned InfoZip, the LZW patent, its connection to the various Bzip2 sites, various nitpicks, and finally the fact that Power Archiver 9.0 can do compression and decompression of .bz2 files.

Not only Bzip2, Power Archiver also natively handles GZip, traditional Zip, both WinZip's and PKZip's proprietary Zip extensions, .tgz (GZipped Tarballs), tbz2 (BZipped Tarballs), even RARs. But the coup-de-gracé, if one would say is its default compression format, which compresses even better than BZip2, called 7z. Now 7Zip is an open source compression format developed by Igor Pavlov for his 7Zip compression utility. Apparently he made an even more optimized version of the LZ77 algorithm for use in his 7Zip program. There are efforts at transferring the algorithm to the Free/Open Source Software world, but it was somewhat hindered because of Pavlov's uses of some proprietary Windows C++ hooks in his source code. But there is some progress being made; they're not quite done yet but its getting very close.

So right now the best widely available compression utility with the best compression ratio is fully available in Windows, but it doesn't make market penetration because of WinZip's very big brand identity. And of course, as usual, constructive laziness;)


Posted at 1:01:40 pm by ferdikom98

 

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I don't write intellectually. I write expressively. I don't claim to be accurate, fair or thorough. I don't wanna get stuck on certain topics. Though I sometimes do. But not that often. I'd like to expand. I wanna write more poems. But I'll only upload them if they're good. I only rant about my life's hardships if it will rescue just a little bit of my sanity. I'm saner than I make myself out to be, though.

If I am an OS kernel, and I just had a kernel dump, I'd imagine that the text in this blog is what it would more or less look like.

There. Do you get it?

   

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