|Written in||C, C++, Objective-C, assembly language|
|Source model||Open source|
|Initial release||November 15, 2000|
|Latest release||19.6.0 (June 1, 2020)|
|Platforms||Current: x86-64, 64-bit ARM|
Historical: PowerPC, IA-32, 32-bit ARM (32-bit ARM support was closed-source)
|Default user interface||Command-line interface|
|License||Mostly Apple Public Source License (APSL), with closed-source drivers|
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Darwin is an open-source Unix-like operating system first released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, Mach, and other free software projects.
Darwin forms the core set of components upon which macOS (previously OS X and Mac OS X), iOS, watchOS, tvOS, and iPadOS are based. It is mostly POSIX-compatible, but has never, by itself, been certified as compatible with any version of POSIX. Starting with Leopard, macOS has been certified as compatible with the Single UNIX Specification version 3 (SUSv3).
The heritage of Darwin began with NeXT's NeXTSTEP operating system (later, since version 4.0, known as OPENSTEP), first released in 1989. After Apple bought NeXT in 1997, it announced it would base its next operating system on OPENSTEP. This was developed into Rhapsody in 1997, Mac OS X Server 1.0 in 1999, Mac OS X Public Beta in 2000, and Mac OS X 10.0 in 2001.
In 1999, Apple announced it would release the Mach 2.5 microkernel, BSD Unix 4.4 OS, and the Apache Web server components of Mac OS X Server. At the time interim CEO Steve Jobs alluded to British naturalist Charles Darwin by announcing "because it's about evolution". In 2000, the core operating system components of Mac OS X were released as open-source software under the Apple Public Source License (APSL) as Darwin; the higher-level components, such as the Cocoa and Carbon frameworks, remained closed-source.
Up to Darwin 8.0.1, Apple released a binary installer (as an ISO image) after each major Mac OS X release that allowed one to install Darwin on PowerPC and Intel x86 systems as a standalone operating system. Minor updates were released as packages that were installed separately. Darwin is now only available as source code, except for the ARM variant, which has not been released in any form separately from iOS, watchOS, or tvOS. A hobbyist developer winocm took the official Darwin source code and ported it to ARM.
The kernel of Darwin is XNU, a hybrid kernel which uses OSFMK 7.3 (Open Software Foundation Mach Kernel) from the OSF, various elements of FreeBSD (including the process model, network stack, and virtual file system), and an object-oriented device driver API called I/O Kit. The hybrid kernel design provides the flexibility of a microkernel[failed verification - see discussion] and the performance of a monolithic kernel.
Darwin currently includes support for the 64-bit x86-64 variant of the Intel x86 processors used in Macs and the 64-bit ARM processors used in the iPhone 5S, the 6th generation iPod Touch, the iPad Air, the fourth generation Apple TV, original HomePod, and later models, as well as the 32-bit ARM processors used in the iPhone 5C and older, earlier generations of the iPod Touch, the iPad up to the fourth generation, and the second and third generation Apple TV. An open-source port of the XNU kernel exists that supports Darwin on Intel and AMD x86 platforms not officially supported by Apple, though it does not appear to have been updated since 2009. An open-source port of the XNU kernel also exists for ARM platforms. Older versions supported some or all of 32-bit PowerPC, 64-bit PowerPC, and 32-bit x86.
It supports the POSIX API by way of its BSD lineage (largely FreeBSD userland) and a large number of programs written for various other UNIX-like systems can be compiled on Darwin with no changes to the source code.
Darwin does not include many of the defining elements of macOS, such as the Carbon and Cocoa APIs or the Quartz Compositor and Aqua user interface, and thus cannot run Mac applications. It does, however, support a number of lesser known features of macOS, such as mDNSResponder, which is the multicast DNS responder and a core component of the Bonjour networking technology, and launchd, an advanced service management framework.
In July 2003, Apple released Darwin under version 2.0 of the Apple Public Source License (APSL), which the Free Software Foundation (FSF) classifies as a free software license incompatible with the GNU General Public License. Previous versions were released under an earlier version of the APSL license, which did not meet the FSF definition of free software, although it did meet the requirements of the Open Source Definition.
The following is a table of major Darwin releases with their dates of release and their corresponding macOS releases. Note that the corresponding macOS release may have been released on a different date; refer to the macOS pages for those dates.
|0.1||March 16, 1999||Mac OS X Server 1.0 releases||
|0.2||April 14, 1999||Mac OS X Server 1.0.1|
|0.3||August 5, 1999||Based on Rhapsody 5.5
|1.0||April 12, 2000||Developer preview 3
|1.1||April 5, 2000||Developer preview 4|
|1.2.1||November 15, 2000||Mac OS X Public Beta (code-named "Kodiak")|
|1.3.1||April 13, 2001||Mac OS X v10.0 (code-named "Cheetah")||
|1.4.1||October 2, 2001||Mac OS X v10.1 (code-named "Puma")|
|5.1||November 12, 2001||Mac OS X v10.1.1
|5.5||June 5, 2002||Mac OS X v10.1.5|
|6.0.1||September 23, 2002||Mac OS X v10.2 (code-named "Jaguar")|
|6.8||October 3, 2003||Mac OS X v10.2.8|
|7.0||October 24, 2003||Mac OS X Panther||Mac OS X v10.3.0|
|7.9||April 15, 2005||Mac OS X v10.3.9|
|8.0||April 29, 2005||Mac OS X v10.4.0|
|8.11||November 14, 2007||Mac OS X v10.4.11|
|9.0||October 26, 2007||Mac OS X v10.5.0
|9.8||August 5, 2009||Mac OS X v.10.5.8|
|10.0||August 28, 2009||Mac OS X v10.6.0
|10.8||June 23, 2011||Mac OS X v10.6.8|
|11.0.0||July 20, 2011||Mac OS X v10.7.0
|11.4.2||October 4, 2012||Mac OS X v10.7.5 (supplemental)|
|12.0.0||February 16, 2012||OS X Mountain Lion||OS X v10.8.0|
|12.6.0||January 27, 2015||OS X v10.8.5 (with Security Update 2015-001)|
|13.0.0||June 11, 2013||OS X v10.9.0
|13.4.0||September 17, 2014||OS X v10.9.5|
|14.0.0||September 18, 2014||OS X v10.10.0|
|14.5.0||August 13, 2015||OS X v10.10.5|
|15.0.0||September 16, 2015||OS X v10.11.0 and iOS 9.0
|15.6.0||July 18, 2016||OS X v10.11.6 and iOS 9.3.3|
|16.0.0||September 13, 2016||macOS v10.12.0 and iOS 10.0.1 (initial release version)
|16.5.0||March 27, 2017||macOS v10.12.4 and iOS 10.3|
|16.6.0||July 19, 2017||macOS v10.12.6 and iOS 10.3.3|
|17.0.0||September 19, 2017||
|17.5.0||March 29, 2018||macOS 10.13.4
|17.6.0||June 1, 2018||macOS v10.13.5|
|17.7.0||July 9, 2018||macOS v10.13.6 and iOS 11.4.1|
|18.0.0||September 24, 2018|
|18.2.0||October 30, 2018||macOS v10.14.1 and iOS 12.1
|19.0.0||September 19, 2019|
|19.2.0||December 10, 2019||macOS 10.15.2 and iOS 13.3|
|19.3.0||January 28, 2020||macOS 10.15.3 and iOS 13.3.1
|19.4.0||March 24, 2020|
|19.5.0||April 30, 2020||macOS 10.15.5 and iOS 13.5|
|19.6.0||June 1, 2020||macOS 10.15.6 beta 2 and iOS 13.6.0 beta 2|
|20.0.0||June 22, 2020||macOS 11.0 beta 1 and iOS 14.0 beta 1|
|20.1.0||September 3, 2020||macOS 11.0 beta 6|
The jump in version numbers from Darwin 1.4.1 to 5.1 with the release of Mac OS X v10.1.1 was designed to tie Darwin to the Mac OS X version and build numbering system, which in turn is inherited from NeXTSTEP. In the build numbering system of macOS, every version has a unique beginning build number, which identifies what whole version of macOS it is part of. Mac OS X v10.0 had build numbers starting with 4, 10.1 had build numbers starting with 5, and so forth (earlier build numbers represented developer releases).
Due to the free software nature of Darwin, there have been projects that aim to modify or enhance the operating system.
OpenDarwin was a community-led operating system based on the Darwin system. It was founded in April 2002 by Apple Inc. and Internet Systems Consortium. Its goal was to increase collaboration between Apple developers and the free software community. Apple benefited from the project because improvements to OpenDarwin would be incorporated into Darwin releases; and the free/open source community benefited from being given complete control over its own operating system, which could then be used in free software distributions such as GNU-Darwin.
On July 25, 2006, the OpenDarwin team announced that the project was shutting down, as they felt OpenDarwin had "become a mere hosting facility for Mac OS X related projects", and that the efforts to create a standalone Darwin operating system had failed. They also state: "Availability of sources, interaction with Apple representatives, difficulty building and tracking sources, and a lack of interest from the community have all contributed to this." The last stable release was version 7.2.1, released on July 16, 2004.
PureDarwin is a project to create a bootable operating system image from Apple's released source code for Darwin. Since the cessation of OpenDarwin and the release of bootable images since Darwin 8.x, it has been increasingly difficult to create a full operating system as many components become closed source. The project has managed to create an Xmas release based on Darwin 9 with an X11 GUI and a command-line only 17.4 Beta based on Darwin 17.
Leopard is now an Open Brand UNIX 03 Registered Product, conforming to the SUSv3 and POSIX 1003.1 specifications for the C API, Shell Utilities, and Threads.