@Jellby --- split/spanned archives. Hmmm. That is an interesting idea. But I don't think Windows' built-in zip utility handles those, and not everybody keeps a third-party tool to handle rar, 7z, etc. (Let me give a recommendation for ArcThemAll, available from
http://arcthemall.sourceforge.net/. Its Free and Open Source, and a pretty nice little tool that can unpack dozens of archive formats, including rar, 7z, zip, tar/gz, etc, and can archive to zip or 7z.) If Windows can handle split archives, I would be interested to know how to do that, because it surely would be useful.