OK Hiroshi, I read some of the comments earlier in the thread that I had missed before (looks like they were sent through RedMine) One of my concerns with using jar files is it requires reading zip files which is not supported by the ruby stdlib. I would like to have the format readable by at least back to 1.8.7 with minimal extra library requirements. On old versions (like 1.8.7) it is probably acceptable to have some required extra libraries, but it would be best if we didn't have a dependency like rubyzip in new versions (1.9 series) just to open the files, and I doubt rubyzip (or similar) will be included in stdlib anytime soon. Does this concern make any sense to you? -Jonathan Nielsen