7z as a much better archiver than gz/bz2

[Alexy Khrabrov]

Greetings -- I've switched to 7z for most of corpora compression, as  
it gives results which are whole number of times better than gz, and  
1.1-1.5 better than bz2.  Would be nice to see it used more,  
especially for the huge kind of things we do here.  E.g., a 4.0 GB lm  
file was compressed by 7za (a command line version for linux) to 642  
MB.  7za is multi-core CPU aware and knows all about locales and  
encodings as well.

http://www.7-zip.org/

Cheers,
Alexy