| > I thought that OS X was mach kernel based, making it a lightweight | > derivative of a BSD kernel, is that right? | not that I know of... I don't think I've heard anything like that. | Yes, it is. They use the Mach 3.0 kernel. The Mach kernel has been around for a long time. (I have a copy of Byte with an article about the Mach kernel for mac from '89) They mention it at the bottom here: http://www.apple.com/macosx/technologies/