XNU, Darwin, macOS/iOS/visionOS/watchOS/tvOS

Posted by binglongx on July 8, 2025

	Brief	Description	Components	History	Other
XNU	OS kernel	Hybrid kernel design with microkernel and monolithic kernel	– Mach/OSFMK: task management, IPC(Mach ports…), scheduling etc; – BSD: Unix APIs, file systems, network stack, user permission, etc; – IOKit: object-oriented C++ drivers	originally part of NeXTSTEP	Open source
Darwin	Core of OS	XNU + core Unix utilities + low-level system frameworks	– XNU: kernel; – BSD userland – libSystem: libc, libpthread, libm, etc; – launchd: service manager; – DriverKit/IOKit: frameworks to write drivers, in kernel (IOKit) or user space (DriverKit)	combines NeXTSTEP, Mach 3.0 and FreeBSD components.	Open source
macOS/iOS/visionOS/watchOS/tvOS/…	Full Unix-like OS	Full OS for general end users	– Darwin: core; – Apple frameworks: Cocoa, Metal, etc; – GUI; – system apps: Safari, Finder etc.		Closed source

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This entry was posted on July 8, 2025 at 7:07 pm and is filed under Computer and Internet. Tagged: Apple, Darwin, iOS, macOS, OS, tvOS, visionOS, watchOS, XNU. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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