XNU
XNU is the kernel that serves as the core of Apple's macOS, iOS, watchOS, and tvOS operating systems. It is a hybrid kernel combining elements of monolithic and microkernel designs, integrating Mach for low-level tasks and BSD for Unix compatibility. XNU handles essential system functions like process management, memory allocation, and device drivers.
Developers should learn XNU when working on Apple platform development, system-level programming, or kernel debugging for macOS or iOS. It is crucial for understanding the underlying architecture of Apple devices, enabling tasks like driver development, security research, or performance optimization at the kernel level. Knowledge of XNU is also valuable for cross-platform developers targeting Unix-like systems.