2 ms·

Their userland is still majorly based on OSFMK, not FreeBSD - to the point where exactly that assumption recently bit me when trying to run program written for

• heavyset_go 6y ago
  > Darwin/XNU/macOS are not FreeBSD based, nor NetBSD based, nor OpenBSD based, even if in places it can take pieces of their code. Apple disagrees[1]: > XNU is a hybrid kernel combining the Mach kernel developed at Carnegie Mellon University with components from FreeBSD From Apple's kernel docs[2]: > Darwin is based on proven technology from many sources. A large portion of this technology is derived from FreeBSD, a version of 4.4BSD that offers advanced networking, performance, security, and compatibility features. XNU has a "personalities" concept, and the BSD personality is mostly just FreeBSD[2]: > Above the Mach layer, the BSD layer provides “OS personality” APIs and services. The BSD layer is based on the BSD kernel, primarily FreeBSD. Even the syscall interface is from FreeBSD. Here's a diagram of macOS architecture[3]. [1] https://github.com/apple/darwin-xnu https://github.com/apple/darwin-xnu [2] https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/KernelProgramming/Architecture/Architecture.html https://developer.apple.com/library/archive/documentation/Da... [3] https://en.wikipedia.org/wiki/File:Diagram_of_Mac_OS_X_architecture.svg https://en.wikipedia.org/wiki/File:Diagram_of_Mac_OS_X_archi...