What Is Darwin (and How It Powers Mac OS X)

Darwin is the Unix-derived core that provides the underlying foundation for Mac OS X. At Darwin’s heart is the XNU kernel–a Mach 3.0-based microkernel that has been modified to include portions of FreeBSD for performance reasons. Darwin includes facilities for creating device drivers, supports multiple file systems through its enhanced Virtual File System (VFS) design, and offers premier networking facilities such as Bonjour, an implementation of zero-configuration networking. Apple releases Darwin under the Apple Public Source License (APSL) 2.0, and organizations such as OpenDarwin.org and GNU-Darwin use this source to periodically release their own custom versions of Darwin in an effort to foster community involvement.