Difference in archive formats?
Archive Utility Preferences
  Use archive format:

Zip archive: A Zip file (.zip).
regular archive: ASCII cpio archive (.cpio).
compressed archive: An ASCII cpio archive, but gzip compressed (.cpgz).

Note that the Compress &quot;folder&quot; option in Finder always creates a zip file. To use the other options you have to open Archive Utility directly and drag-and-drop things onto the icon in the Dock.