Greetings! First of all, let me just say that, unfortunatelly, I have no experience of whatsoever using Mac OSX, so I guess that fact may explain my next question (in case it's something every Mac user already knows ). I was told that Aqua is nothing more than a window manager, or better said desktop environment, running on top of X server - just like kde/gnome in linux/*bsd world. Now, looking at the Mac OSX architecture overview, I can't help thinking that it's not really the case. X11 for Mac seems to be a standard part of the OSX from the version 10.3, so Aqua (in previous versions of OSX) can't be running on top of it?! Furthermore, X11 is always described as a part of OSX that's sole purpose is to provide the means to run classic unix X apps. So, my question is: "Is Aqua really a WM/DE running on top of some kind of X server? Or not?"