iOS based on Mach based Darwin.

I was reading the Web+DB Press Vol.58, and learned that iOS is based on open source microkernel, Mach based Darwin. Quite interesting how even iOS is based on open source kernel. Well, that is understandable since Mac OS X is based on UNIX.

http://www.roughlydrafted.com/2007/07/13/iphone-os-x-architecture-the-mach-kernel-and-ram/ is a good reference.