> >> Mac os x has a feature that allows 'fat' binaries; i.e. binaries > > > with > >> multiple architectures. > > > > This is only on the userland side of things > > that is for *applications* > > since it's the OS that handles them. > > The OS itself, let alone the bootloader likely is x86 only. > > > Well, I know, for example, that their install cds work on both > architectures... They do a universal boot somehow. Ok but that doesn't involve universal binaries. It just have both loaders. BeOS R5 Pro CDs were also bootable on both PPC and intel AFAIK. François.