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 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.
An open-source port of the XNU kernel exists that supports Darwin on Intel and AMD x86 platforms not officially supported by Apple, although it does not appear to have been updated since 2009.
It does, however, support a number of lesser known features of mac OS, such as m DNSResponder, 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.
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 Ne XTSTEP.
In the build numbering system of mac OS, every version has a unique beginning build number, which identifies what whole version of mac OS it is part of.
In the case of Mac OS X v10.1.1 (the version where the jump in version numbers was made), this was build 5M28 and the 10.1.1 release, from which a version number of 5.1 was derived.
will show the XNU build version string, which includes the Darwin version number.
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 Darwin developers decided to adopt a mascot in 2000, and chose Hexley the Platypus, over other contenders, such as an Aqua Darwin fish, Clarus the Dogcow, and an orca.
Darwin is an open-source Unix operating system released by Apple Inc. It is composed of code developed by Apple, as well as code derived from Ne XTSTEP, BSD, Mach, and other free software projects.
Darwin forms the core set of components upon which mac OS (previously OS X and Mac OS X), i OS, watch OS, and tv OS are based.
Hexley is a cartoon platypus who – mimicking the BSD Daemon – usually wears a cap resembling a demon's horns and carries a trident which symbolizes the forking of processes. Apple does not sanction Hexley as a logo for Darwin.