Darwin is the core

Unix-like A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

macOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

, iOS,

watchOS watchOS is the operating system of the Apple Watch, developed by Apple Inc., Apple. It is based on iOS, the operating system used by the iPhone, and has many similar features. It was released on April 24, 2015, along with the Apple Watch, the o ...

tvOS tvOS (formerly Apple TV Software) is an operating system developed by Apple for the Apple TV, a digital media player. In the first-generation Apple TV, Apple TV Software was based on Mac OS X. The software for the second-generation and later ...

iPadOS 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, suc ...

audioOS The HomePod is a series of smart speakers developed by Apple. Designed to work with the Apple Music subscription service, the HomePod incorporates beamforming and eight speakers and is sold in two colors: white and midnight. It is sold alongs ...

, visionOS, and bridgeOS. It previously existed as an independent

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

operating system, first released by

Apple Inc. Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Comput ...

in 2000. It is composed of code derived from

NeXTSTEP 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 ...

FreeBSD FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...

and other

BSD The Berkeley Software Distribution (BSD), also known as Berkeley Unix or BSD Unix, is a discontinued Unix operating system developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley, beginni ...

operating systems,

Mach The Mach number (M or Ma), often only Mach, (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a Boundary (thermodynamic), boundary to the local speed of sound. It is named after the Austrian physi ...

, and other

free software Free software, libre software, libreware sometimes known as freedom-respecting software is computer software distributed open-source license, under terms that allow users to run the software for any purpose as well as to study, change, distribut ...

projects' code, as well as code developed by Apple. Darwin's unofficial mascot is Hexley the Platypus. Darwin is mostly

POSIX The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with comm ...

-compatible, but has never, by itself, been certified as compatible with any version of POSIX. Starting with

Leopard The leopard (''Panthera pardus'') is one of the five extant cat species in the genus ''Panthera''. It has a pale yellowish to dark golden fur with dark spots grouped in rosettes. Its body is slender and muscular reaching a length of with a ...

, macOS has been certified as compatible with the

Single UNIX Specification The Single UNIX Specification (SUS) is a standard for computer operating systems, compliance with which is required to qualify for using the "UNIX" trademark. The standard specifies programming interfaces for the C language, a command-line shell, ...

version 3 (SUSv3).

History

The heritage of Darwin began with Unix derivatives supplemented by aspects of

NeXT NeXT, Inc. (later NeXT Computer, Inc. and NeXT Software, Inc.) was an American technology company headquartered in Redwood City, California that specialized in computer workstations for higher education and business markets, and later develope ...

operating system (later, since version 4.0, known as OPENSTEP), first released in 1989. After Apple bought NeXT in 1996, 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 Mac OS X Public Beta (internally code named "Kodiak") was the first publicly available version of Apple Inc., Apple Computer's macOS, Mac OS X (now named macOS) operating system to feature the Aqua (user interface), Aqua user interface. It was ...

in 2000, and Mac OS X 10.0 in 2001. In 1999, Apple announced it would release the source code for the Mach 2.5 microkernel, BSD Unix 4.4 OS, and the

Apache Web server The Apache HTTP Server ( ) is a free and open-source cross-platform web server, released under the terms of Apache License 2.0. It is developed and maintained by a community of developers under the auspices of the Apache Software Foundation. ...

components of Mac OS X Server. At the time, interim CEO

Steve Jobs Steven Paul Jobs (February 24, 1955 – October 5, 2011) was an American businessman, inventor, and investor best known for co-founding the technology company Apple Inc. Jobs was also the founder of NeXT and chairman and majority shareholder o ...

alluded to British naturalist

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English Natural history#Before 1900, naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all speci ...

by announcing "because it's about evolution". In 2000, the core operating system components of Mac OS X were released as

open-source software Open-source software (OSS) is Software, computer software that is released under a Open-source license, license in which the copyright holder grants users the rights to use, study, change, and Software distribution, distribute the software an ...

under the

Apple Public Source License The Apple Public Source License (APSL) is the open-source and free software license under which Apple's Darwin operating system was released in 2000. A free and open-source software license was voluntarily adopted to further involve the commu ...

(APSL) as Darwin; the higher-level components, such as the Cocoa and

Carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

frameworks, remained closed-source. Up to Darwin 8.0.1, released in April 2005, Apple released a binary installer (as an ISO image) after each major Mac OS X release that allowed one to install Darwin on

PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple Inc., App ...

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. As of January 2023, Apple no longer mentions Darwin by name on it
Open Source website
and only publishe
an incomplete collection of open-source projects relating to macOS and iOS

Design

Kernel

The kernel of Darwin is XNU, a

hybrid kernel A hybrid kernel is an operating system Kernel (operating system), kernel whose architecture attempts to combine aspects and benefits of microkernel and monolithic kernel architectures used in operating systems. Overview The traditional kernel cat ...

which uses OSFMK 7.3 (Open Software Foundation Mach Kernel) from the OSF, various elements of

(including the process model, network stack, and

virtual file system A virtual file system (VFS) or virtual filesystem switch is an abstract layer on top of a more concrete file system. The purpose of a VFS is to allow client applications to access different types of concrete file systems in a uniform way. A VFS ...

), and an object-oriented

device driver In the context of an operating system, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabli ...

API An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build ...

called I/O Kit. The hybrid kernel design provides the flexibility of a

microkernel In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, ...

and the performance of a

monolithic kernel A monolithic kernel is an operating system software architecture, architecture with the entire operating system running in kernel space. The monolithic model differs from other architectures such as the microkernel in that it alone defines a high ...

Hardware and software support

The last bootable full release of Darwin supported 32-bit and 64-bit Apple PowerPC systems and 32-bit Intel PCs. Darwin currently includes support for the

64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit central processing units (CPU) and arithmetic logic units (ALU) are those that are based on processor registers, a ...

x86-64 x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit extension of the x86 instruction set architecture, instruction set. It was announced in 1999 and first available in the AMD Opteron family in 2003. It introduces two new ope ...

variant of the Intel x86 processors used in Intel-based Macs and the 64-bit ARM processors used in the iPhone 5S and later, the 6th generation iPod Touch, the 5th generation iPad and later, the iPad Air family, the iPad Mini 2 and later, the iPad Pro family, the fourth generation and later

Apple TV Apple TV is a digital media player and a microconsole developed and marketed by Apple. It is a small piece of networking hardware that sends received media data such as video and audio to a TV or external display. Its media services include ...

s, the

HomePod The HomePod is a series of smart speakers developed by Apple Inc., Apple. Designed to work with the Apple Music subscription service, the HomePod incorporates beamforming and eight speakers and is sold in two colors: white and midnight. It is s ...

family, and Macs with

Apple silicon Apple silicon is a series of system on a chip (SoC) and system in a package (SiP) processors designed by Apple Inc., mainly using the ARM architecture family, ARM architecture. They are used in nearly all of the company's devices including Mac ...

such as the 2020 Apple M1 Macs, as well as the Raspberry Pi 3B. An open-source port of the XNU kernel exists that supports Darwin on Intel and

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational corporation and technology company headquartered in Santa Clara, California and maintains significant operations in Austin, Texas. AMD is a hardware and fabless company that de ...

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, though it has not been updated since 2016. Older versions supported some or all of 32-bit

, 64-bit PowerPC, 32-bit x86, and 32-bit ARM. It supports the

API by way of its

lineage (largely

userland), so a large number of programs written for various other

UNIX-like A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...

systems can be compiled on Darwin with no changes to the

source code In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer. Since a computer, at base, only ...

. Darwin does not include many of the defining elements of macOS, such as the

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 In computer networking, multicast is a type of group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast differs from ph ...

DNS responder and a core component of the Bonjour networking technology, and launchd, an advanced

service management Service management in the manufacturing context, is integrated into supply chain management as the intersection between the actual sales and the customer point of view. The aim of high-performance service management is to optimize the service- ...

framework.

License

In July 2003, Apple released Darwin under version 2.0 of the

(APSL), which the

Free Software Foundation The Free Software Foundation (FSF) is a 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985. The organisation supports the free software movement, with the organization's preference for software being distributed ...

(FSF) classifies as a

free software license A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder (usually the author) ...

incompatible with the

GNU General Public License The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses, or ''copyleft'' licenses, that guarantee end users the freedom to run, study, share, or modify the software. The GPL was the first ...

. 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.

Release history

The following is a table of major Darwin releases with their dates of release and their derivative operating system releases. Note that the corresponding releases may have been released on a different date.

Darwin 0–8 and corresponding Mac OS X releases

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).

Darwin 9; iPhone OS introduced

Darwin 10-11; iPhone OS rebranded to iOS

Darwin 12–15; Mac OS X rebranded into OS X

Darwin 16–19; OS X rebranded into macOS

Darwin 20 onwards

''Note: the tables above contain the release dates of the corresponding OS releases. Build dates for Darwin versions are not publicly available; the commands below only give the build date for the XNU kernel.'' The command in Terminal will show the Darwin version number ("20.3.0"), and the command will show the XNU build version string, which includes the Darwin version number. The command will show the corresponding ProductName ("macOS"), the ProductVersion number ("11.2.3") and the BuildVersion string ("20D91").

Derived projects

Due to the free software nature of Darwin, there have been projects that aim to modify or enhance the operating system.

OpenDarwin

OpenDarwin was a community-led operating system based on the Darwin system. It was founded in April 2002 by

and Internet Systems Consortium. Its goal was to increase collaboration between Apple developers and the

free software community The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedoms to run, study, modify, and share copies of software. Software which meets these requirements, ...

. 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

PureDarwin is a project to create a bootable operating system image from Apple's released source code for Darwin. Since the halt 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 became closed source. In 2015 the project created a preview release based on Darwin 9 with an X11 GUI, followed by a command-line only 17.4 Beta based on Darwin 17.

Other derived projects

* XQuartz is a component of the

X Window System The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems. X originated as part of Project Athena at Massachusetts Institute of Technology (MIT) in 1984. The X protocol has been at ...

that runs on

(Darwin). XDarwin, before the introduction of Apple's X11.app. *

GNUstep GNUstep is a free software implementation of the Cocoa (formerly OpenStep) Objective-C frameworks, widget toolkit, and application development tools for Unix-like operating systems and Microsoft Windows. It is part of the GNU Project. GNUst ...

is a

implementation of the Cocoa (formerly

OpenStep OpenStep is an object-oriented application programming interface (API) specification developed by NeXT. It provides a framework for building graphical user interfaces (GUIs) and developing software applications. OpenStep was designed to be plat ...

)

Objective-C Objective-C is a high-level general-purpose, object-oriented programming language that adds Smalltalk-style message passing (messaging) to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was ...

frameworks,

widget toolkit A widget toolkit, widget library, GUI toolkit, or UX library is a library (computing), library or a collection of libraries containing a set of graphical control elements (called ''widgets'') used to construct the graphical user interface (GUI) of ...

, and application development tools for

s. * Window Maker, a window manager designed to emulate the

GUI as part of the wider GNUstep project. *

WebKit WebKit is a browser engine primarily used in Apple's Safari web browser, as well as all web browsers on iOS and iPadOS. WebKit is also used by the PlayStation consoles starting with the PS3, the Tizen mobile operating systems, the Amazon K ...

is a

browser engine A browser engine (also known as a layout engine or rendering engine) is a core software component of every major web browser. The primary job of a browser engine is to transform HTML documents and other resources of a web page into an interacti ...

primarily used in Apple's

Safari A safari (; originally ) is an overland journey to observe wildlife, wild animals, especially in East Africa. The so-called big five game, "Big Five" game animals of Africa – lion, African leopard, leopard, rhinoceros, African elephant, elep ...

web browser, as well as all web browsers on iOS and

. * MacPorts (formerly DarwinPorts), Fink, and Homebrew are projects to port UNIX programs to the Darwin operating system and provide package management. In addition, several standard UNIX package managers—such as RPM,

pkgsrc pkgsrc (''package source'') is a package management system for Unix-like operating systems. It was forked from the FreeBSD ports collection in 1997 as the primary package management system for NetBSD. Since then it has evolved independently; in 1 ...

, and

Portage Portage or portaging ( CA: ; ) is the practice of carrying water craft or cargo over land, either around an obstacle in a river, or between two bodies of water. A path where items are regularly carried between bodies of water is also called a '' ...

—have Darwin ports. Some of these operate in their own namespace so as not to interfere with the base system. * GNU-Darwin was a project that ports packages of free software to Darwin. They package OS images in a way similar to a

Linux distribution A Linux distribution, often abbreviated as distro, is an operating system that includes the Linux kernel for its kernel functionality. Although the name does not imply product distribution per se, a distro—if distributed on its own—is oft ...

. * The Darwine project was a

port A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Hamburg, Manch ...

Wine Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...

that allows one to run

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

software on Darwin. * SEDarwin was a port of TrustedBSD mandatory access control framework and portions of the SELinux framework to Darwin. It was incorporated into Mac OS X 10.5. * The Darbat project was an experimental port of Darwin to the L4 microkernel family. It aims to be binary compatible with existing Darwin binaries. * The Darling project is a compatibility layer for running macOS binaries on Linux systems. It uses some Darwin source code. * There are various projects that focus on driver support: e.g., wireless drivers, wired NIC drivers modem drivers, card readers, and the

ext2 ext2, or second extended file system, is a file system for the Linux kernel (operating system), kernel. It was initially designed by French software developer Rémy Card as a replacement for the extended file system (ext). Having been designed ...

and

ext3 ext3, or third extended filesystem, is a journaling file system, journaled file system that is commonly used with the Linux kernel. It used to be the default file system for many popular Linux distributions but generally has been supplanted by ...

file systems. * DarwinBSD Project is a Darwin project using pkgsrc for packages. It is an open source project.

References

External links

Darwin Releases
at Apple Developer Connection
source code of individual packages

Hexley, the Darwin mascot

PureDarwin.org
* {{DEFAULTSORT:Darwin (Operating System) 2000 software Mascots introduced in 2000 Animal mascots Apple Inc. operating systems Berkeley Software Distribution Fictional monotremes Free software operating systems Mach (kernel) MacOS Software version histories Unix variants IA-32 operating systems X86-64 operating systems