I was having an iteleectual AIM session with killyp here from macrumors (He's studying for GSCE's) and we were discussing Mac's and PC's. It came to something very awkward involving PPC's x86's and windows+mac OS X. So here is goes, from the start... Old mac's had PPC chips and run OS X New Mac's have Intel chips and run OS X PC's have x86 chips and run windows The above is all generalised. So, Mac's can all run universal binary .app's but cannot run .exe's. This is because .exe's are based on the windows API, right? but now that macs have intel processors they can have windows installed on them (some of my PC friends -acquaintances- don't understand this yet) and therefore macs can run .exe's. But mac's run PPC code via rosetta emulation and old PPC macs could run windows via emulation (Virtual PC) so everyone can run every code except PC's which can't run PPC code. Again, this is a generalisation. So then Alex says that teher is some port of windows to PPC adn I told him that even if it was true (NT was ported to PPC for a short while) It wouldn't be able to run .exe apps as the chip is not compatible to which he replied taht the proramme doesn't communicate with the processor at a machine code level and taht teh OS did all of that. To which I formulated my view on Rosetta emulation that even though an inteal mac runs OS X it does not natively support PPC code. What I am wondering is: why cant (EDITed3)PPC coded apps and x86 coded .exe's work on teh same processor natively? I think this is my question, I'm sure there must be various other views or thought about the compatibility. EDIT1: The react OS states that they can achieve compatibility of windows apps on a PPC system. Is this all lies or is some truth involved? EDIT2: I know that x11 code (unix code) is compatible on mac OS X as it is in Linux and Windows. Is this similar to how how java uses a virtual machine to work on many OSes?