Relation of BSD stuff to OS X

Spotted on Slashdot:

Not to nitpick or anything, but…

I hear this all the time. OS X is NOT “just BSD with some apple stuff slapped on top.” It’s not even truly BSD. It’s a Mach Microkernel with a BSD Compatibility layer on top. That means it replicates the BSD system calls but is not truly a BSD Kernel. It’s kinda like saying WINE is windows. It’s just an implementation of an API. Granted, the OS X implementation is a lot truer to correctly pretending to be BSD than wine is for windows, but it is NOT BSD. It just incorporates a lot of the BSD stuff that apple found useful