Zmarties

Whilst there are many file formats that offer better compression, the ZIP file format is still very widely used, and in fact experiencing a surge in popularity again, since it is the basis for a number of other file formats, including

• jar files used in Java
• kmz (compressed kml) files used by Google Earth
• Microsoft's upcoming xml and zip based Office document format
• OpenOffice's document format

With this in mind, I did a quick and largely unscientific test of a number of Windows based command line zip utilities, to see which one produced the smallest files. In all cases, I set the parameters to give what I believed was the most compression. I was compressing just one file at a time (since that was what my particular scenario needed).

The results were:

• pkzip command line version 4.0 (parameters -level=9) produced a compressed file which I considered my baseline file size
  
• info-zip version 2.31 (parameters -J -X -j -9) produced a file that was about 0.5% smaller than the baseline until the compressed file size was about 3K, at which point the file size tended to be about 1% larger than the baseline file size
  
• 7-Zip version 4.23 (parameters -tzip -mx9 -mpass=4 -mfb=255) produced a file that matched the best of the previous two for very small compressed file sizes
  

So the overall winner was 7-Zip - across my selection of 42 files of varing sizes, it produced a total compressed size of 104K, compared to 109K for each of the other 2 programs.