Mach (kernel)

macOS (previously OS X and originally Mac OS X) is a proprietary Unix operating system, derived from OPENSTEP for Mach and FreeBSD, which has been marketed and developed by Apple since 2001. It is the current operating system for Apple's line of Mac computers. Within the market of desktop and laptop computers, it is currently the second most widely used desktop OS, after Microsoft Windows and ahead of all Linux distributions, including ChromeOS and SteamOS. , the most recent release of macOS is macOS 26 Tahoe, the 22nd major version of macOS.

iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple for its iPhone line of smartphones. It was unveiled in January 2007 alongside the first-generation iPhone, and was released in June 2007. Major versions of iOS are released annually; the current stable version, iOS 26, was released to the public on September 15, 2025.

GNU ( ) is an extensive collection of free software (387 packages ), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popularly known as Linux. Most of GNU is licensed under the GNU Project's own General Public License (GPL).

iPadOS is a mobile operating system developed by Apple for its iPad line of tablet computers. It was given a name distinct from iOS, the operating system used by Apple's iPhones, to reflect the diverging features of the two product lines, such as multitasking. It was introduced as iPadOS 13, reflecting its status as the successor to iOS 12 for the iPad, and first released to the public on September 24, 2019. Major versions of iPadOS are released annually; the current stable version, , was released to the public on .

core Unix-like operating system of macOS, iOS, etc.

NeXTSTEP is a discontinued object-oriented, multitasking operating system based on the Mach kernel and the UNIX-derived BSD. It was developed by NeXT, founded by Steve Jobs, in the late 1980s and early 1990s and was initially used for its range of proprietary workstation computers such as the NeXT Computer. It was later ported to several other computer architectures and was later bought by Apple Inc. to replace the older Classic Mac OS with macOS.

XNU ("X is Not Unix") is the computer operating system (OS) kernel developed at Apple Inc. since December 1996 for use in the Mac OS X (now macOS) operating system and released as free and open-source software as part of the Darwin OS, which, in addition to being the basis for macOS, is also the basis for iOS, iPadOS, watchOS, visionOS, and tvOS.

operating system kernel

operating system

visionOS is an extended reality operating system derived primarily from iPadOS and its core frameworks (including UIKit, SwiftUI, ARKit and RealityKit), and MR-specific frameworks for foveated rendering and real-time interaction. It was developed by Apple exclusively for its Apple Vision Pro mixed reality headset. It was unveiled on June 5, 2023, at Apple's WWDC23 event alongside the reveal of the Apple Vision Pro. The software released on February 2, 2024, shipping with the Apple Vision Pro.

fourth major release of iPadOS, the tablet operating system developed by Apple Inc.

mobile operating system of the iPad

2021 iPad operating system

operating system

operating system kernel

mobile operating system of the iPad

MkLinux (Microkernel Linux) is a discontinued open-source experimental operating system for PowerPC Macintosh computers. It was launched in 1995 as a collaboration between the Open Software Foundation (OSF) and Apple Computer, as a critical pivot in Apple's technical and social history. MkLinux became Apple's first official free and open-source software community project, and the debut of Linux on the first Power Macintosh.

Mach-O (Mach object) is a file format for executables, object code, shared libraries, dynamically loaded code, and core dumps. It was developed to replace the a.out format.