File talk:Diagram of Mac OS X architecture.svg

The diagram has mistakes. The Darwin is not called as "Core OS". It is called as "development platform". The XNU is not a kernel but a operating system. And the Mach is the microkernel. Now the diagram is saying that inside a kernel (XNU, so called "hybrid kernel" what is marketing and not science) is a kernel (Mach 3.0 what is a real microkernel). And inside of OS (Darwin, mistakenly called "OS") is a OS (XNU, the real OS).