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Does KGB Archiver really achieve high compression rates?

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Lashiec:
I used the word scam because I heard about it on forums with claims of near 1% compression ratios. But in fairness those claims were being made by others, it's own website doesn't make such a claim so I've changed the title of the thread as to not imply deceit on the developers part.
-Eóin (March 24, 2008, 04:29 AM)
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Yeah, I read that somewhere recently and I was all like "WTF?". It's hard to go beyond current compression ratios, and with modern technology (and specialized algorithms for certain data like tinjaw mentions), it's not worth the work of creating a new scheme, and waste tons of CPU time just to squeeze a few megabytes.

I remember that a friend showed me a couple of years ago a super-compressed package of data whose creators claimed impressive ratios, but at the cost of really long decompression times (which I witnessed first hand). Now, if I could remember where did it come from...

nosh:
You could compress something like 1 GB to under 5 KB, it all depends on what you're compressing. ;)
I'd upload the file but I'm scared some forum AV might try to peek into it.

Carol Haynes:
I compressed a VirtualBox VDI (virtual disk image) file of a Server 2008 install. That's 5.8 GB uncompressed.
-Eóin (March 23, 2008, 07:44 PM)
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Ah but is it uncompressed? If you are downloading a virtual disc there is an emphasis on the image being as compacted as possible so have the builders of the image turned on disc compression in Windows when they were packaging it up? Also there are loads of CAB files which are already compressed.

Having said that if 7-zip can do a better job in 45 minutes (not exactly known for its speed either) then what is the point of KGB ?

Eóin:
Having said that if 7-zip can do a better job in 45 minutes (not exactly known for its speed either) then what is the point of KGB ?
-Carol Haynes (March 24, 2008, 08:03 PM)
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That's really the only comparison I was making. I gave it the random test to see how much it would beat 7-zip by so I could then make a subjective decision as to if the extra time needed could still be justified in certain cases. The compression ratio itself I wasn't worried about because as already pointed out that depends very much on the data.

That it produced bigger archives than 7-zip really surprised me and left me bewildered :)

Renegade:
Don't forget that content matters. A lot. Different compression schemes will work better with different types of files. Check Maximum Compression and have a look. It's a bit dense as there are so many there, but you'll see that pan out.

The 4 basic areas for compression algorithms are:

1) Audio
2) Video
3) Images
4) Data (always lossless)

The first 3 have their own specific algorithms. e.g. AC3 compression, MPEG-2 compression, JPEG compression. Most data compression schemes will not yield significant improvements over those. PAQ will usually, but at a high CPU cost.

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