Hi Michael: Michael Maibaum wrote: > As you say, gcc for sure. I presume XL{F|C} will also - derived from > POWER I see no reason why they won't but I don't have any facts. I think it is a library issue in the end, which ABI the code will generate for. If the ABI doesn't need to change, then that is very good news (and I would like to hear about that!). Sometimes though, the reasons that the things don't work the way you expect has little to do with the technical aspects and much to do with marketing/positioning. Would IBM willfully contribute a compiler that generates 64 bit code on a Mac (OSX), when it is trying to sell its own PPC based 64 bit hardware which does not run MacOSX? That is the $64 question. Joe -- Joseph Landman, Ph.D Founder and CEO Scalable Informatics LLC, email: landman at scalableinformatics.com web : http://www.scalableinformatics.com phone: +1 734 786 8423 fax : +1 734 786 8452 cell : +1 734 612 4615