For anybody who may even be remotely interested MacOS 10.5 (Leopard) is a 64 bit OS and allows you to build and run 64 bit binaries. The current Firebird build for MacOS 10.4 and MacOS 10.5 is 32bit. I now have a 64bit build for Leopard. When I get the chance I will explain exactly what was done. I think we will start offering 64bit builds for MacOS with Firebird 2.1 for those who want them.