XNU
Legacy mirror of Darwin Kernel
Darwin XNU is the hybrid kernel that powers Apple’s macOS, iOS, watchOS, and tvOS operating systems, forming the foundation of the Darwin open-source core. The name XNU stands for X is Not Unix, highlighting its origin as a combination of multiple kernel technologies—primarily the Mach microkernel from Carnegie Mellon University, integrated with substantial components from FreeBSD and Apple’s proprietary IOKit driver framework.