Darwin is an

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

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

first released by

Apple Inc. Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company ...

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 Computer in the late 1980s and early 1990s and was initially used for its range of proprieta ...

BSD The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berk ...

, Mach, and other

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

projects' code, as well as code developed by Apple. Darwin forms the Unix-based core set of components upon which

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...

(previously OS X and Mac OS X),

iOS iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone; the term also include ...

watchOS watchOS is the operating system of the Apple Watch, developed by Apple Inc. 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 only dev ...

tvOS tvOS (formerly known as Apple TV Software) is an operating system developed by Apple Inc. for the Apple TV, a digital media player. In the first-generation Apple TV, Apple TV Software was based on Mac OS X. Starting with the second-generation ...

iPadOS iPadOS is a mobile operating system developed by Apple Inc. for its iPad line of tablet computers. It is a rebranded variant of iOS, the operating system used by Apple's iPhones, renamed to reflect the diverging features of the two product l ...

and

bridgeOS bridgeOS is a mobile operating system created and developed by Apple Inc. for use exclusively with its hardware. bridgeOS runs on the T series Apple silicon processors and operates the OLED touchscreen strip called the " Touch Bar" as well as ...

are based. It 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 both the system- and user-level application programming interf ...

-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 species in the genus '' Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, a ...

, macOS has been certified as compatible with the Single UNIX Specification version 3 (SUSv3).

History

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

NeXT Next may refer to: Arts and entertainment Film * ''Next'' (1990 film), an animated short about William Shakespeare * ''Next'' (2007 film), a sci-fi film starring Nicolas Cage * '' Next: A Primer on Urban Painting'', a 2005 documentary film Lit ...

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 Rhapsody may refer to: * A work of epic poetry, or part of one, that is suitable for recitation at one time ** Rhapsode, a classical Greek professional performer of epic poetry Computer software * Rhapsody (online music service), an online m ...

in 1997, Mac OS X Server 1.0 in 1999,

Mac OS X Public Beta The 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 ...

in 2000, and

Mac OS X 10.0 Mac OS X 10.0 (code named Cheetah) is the first major release of macOS, Mac OS X, Apple Computer, Apple's desktop and server operating system. It was released on March 24, 2001 for a price of $129 after a Mac OS X Public Beta, public beta. Mac ...

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

CEO A chief executive officer (CEO), also known as a central executive officer (CEO), chief administrator officer (CAO) or just chief executive (CE), is one of a number of corporate executives charged with the management of an organization especially ...

Steve Jobs Steven Paul Jobs (February 24, 1955 – October 5, 2011) was an American entrepreneur, industrial designer, media proprietor, and investor. He was the co-founder, chairman, and CEO of Apple; the chairman and majority shareholder of Pixar; a ...

alluded to

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, ...

naturalist

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...

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 computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Op ...

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 communit ...

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

Cocoa Cocoa may refer to: Chocolate * Chocolate * ''Theobroma cacao'', the cocoa tree * Cocoa bean, seed of ''Theobroma cacao'' * Chocolate liquor, or cocoa liquor, pure, liquid chocolate extracted from the cocoa bean, including both cocoa butter and ...

and

Carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...

frameworks, remained

closed-source Proprietary software is software that is deemed within the free and open-source software to be non-free because its creator, publisher, or other rightsholder or rightsholder partner exercises a legal monopoly afforded by modern copyright and inte ...

. Up to Darwin 8.0.1, Apple released a binary installer (as an

ISO image An optical disc image (or ISO image, from the ISO 9660 file system used with CD-ROM media) is a disk image that contains everything that would be written to an optical disc, disk sector by disc sector, including the optical disc file system. ...

) 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 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was intr ...

systems as a standalone operating system. Minor updates were released as packages that were installed separately. Darwin is now only available as source code. Unix timeline

Design

Kernel

The kernel of Darwin is XNU, a

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

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

FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...

(including the process model,

network stack The protocol stack or network stack is an implementation of a computer networking protocol suite or protocol family. Some of these terms are used interchangeably but strictly speaking, the ''suite'' is the definition of the communication protoco ...

, 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 computing, 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, enabling operating systems and ot ...

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

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 architecture where the entire operating system is working in kernel space. The monolithic model differs from other operating system architectures (such as the microkernel architecture) in that it alone ...

Hardware and software support

Darwin currently includes support for the

64-bit In computer architecture, 64-bit Integer (computer science), integers, memory addresses, or other Data (computing), data units are those that are 64 bits wide. Also, 64-bit central processing unit, CPUs and arithmetic logic unit, ALUs are those ...

x86-64 x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mod ...

variant of the

processors A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, ...

used in Intel-based Macs and the 64-bit

ARM In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...

processors used in the iPhone 5S and later, the 6th generation iPod Touch, the 5th generation iPad and later, the

iPad Air The iPad is a brand of iOS and iPadOS-based tablet computers that are developed by Apple Inc. The iPad was conceived before the related iPhone but the iPhone was developed and released first. Speculation about the development, operating ...

family, the

iPad Mini 2 The iPad Mini 2 (formerly marketed as the iPad mini with Retina display, officially iPad mini 2 with Retina display) is a tablet computer produced and marketed by Apple Inc. It has a nearly identical design to its predecessor the first-genera ...

and later, the

iPad Pro The iPad Pro is a premium model of Apple's iPad tablet computer. It runs iPadOS, a tablet-optimized version of the iOS operating system. The original iPad Pro was introduced in September 2015, and ran iOS 9. The second-generation iPad P ...

family, the fourth generation and later

Apple TV An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

s, the

HomePod The HomePod is a smart speaker developed by Apple Inc. The HomePod was designed to work with the Apple Music subscription service. The HomePod was announced on June 5, 2017, at the Apple Worldwide Developers Conference. Its launch was later d ...

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. It is the basis of most new Mac computers as well as iPhone, iPad, iPod Touch, Apple TV, ...

such as the 2020

Apple M1 Apple M1 is a series of ARM-based systems-on-a-chip (SoCs) designed by Apple Inc. as a central processing unit (CPU) and graphics processing unit (GPU) for its Mac desktops and notebooks, and the iPad Pro and iPad Air tablets. The M1 c ...

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 semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...

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

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

API by way of its

lineage (largely

userland) and a large number of programs written for various other

UNIX-like A Unix-like (sometimes referred to as UN*X 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 Unix-li ...

systems can be

compiled In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...

on Darwin with no changes to the

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...

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

and

APIs or the

Quartz Compositor Quartz Compositor is the display server (and at the same time the compositing window manager) in macOS. It is responsible for presenting and maintaining rasterized, rendered graphics from the rest of the Core Graphics framework and other ren ...

and

Aqua user interface Aqua is the graphical user interface, design language and visual theme of Apple's macOS operating system. It was originally based on the theme of water, with droplet-like components and a liberal use of reflection effects and translucency. Its ...

, 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 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 should not be confused with ...

DNS The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned to ...

responder and a core component of the

Bonjour Bonjour is a French word meaning (literally translated) "good day", and is commonly used as a greeting. Bonjour may also refer to: People * Laurence BonJour (born 1943), epistemologist and professor of philosophy at the University of Washington ...

networking technology, and

launchd launchd is an init and operating system service management daemon created by Apple Inc. as part of macOS to replace its BSD-style init and SystemStarter. There have been efforts to port launchd to FreeBSD and derived systems. Components Th ...

, 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 A framework is a generic term commonly referring to an essential supporting structure which other things are built on top of. Framework may refer to: Computing * Application framework, used to implement the structure of an application for an op ...

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)#501(c)(3), 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985, to support 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 License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the Four Freedoms (Free software), four freedoms to run, study, share, and modify the software. The license was th ...

. 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 Open Source Definition'' is a document published by the Open Source Initiative, to determine whether a software license can be labeled with the open-source certification mark. The definition was taken from the exact text of the Debian Free ...

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

The command in

Terminal Terminal may refer to: Computing Hardware * Terminal (electronics), a device for joining electrical circuits together * Terminal (telecommunication), a device communicating over a line * Computer terminal, a set of primary input and output dev ...

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 the software, to study the software, to modify the software, and to share copies of the ...

. 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 become 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

MacPorts MacPorts, formerly DarwinPorts, is a package manager for macOS and Darwin. It is an open-source software project that aims to simplify the installation of other open source software. It's similar in function to Fink and the BSD ports collection ...

(formerly DarwinPorts), Fink, and Homebrew are projects to port UNIX programs to the Darwin operating system and provide

package management A package manager or package-management system is a collection of software tools that automates the process of installing, upgrading, configuring, and removing computer programs for a computer in a consistent manner. A package manager deals w ...

. In addition, several standard UNIX package managers—such as

RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionl ...

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 19 ...

, and

Portage Portage or portaging (Canada: ; ) 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 is 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 made from a software collection that includes the Linux kernel and, often, a package management system. Linux users usually obtain their operating system by downloading one ...

. * The

Darwine Wine (formerly a recursive backronym for ''Wine Is Not an Emulator'', now just "Wine") is a free and open-source compatibility layer that aims to allow application software and computer games developed for Microsoft Windows to run on Unix-like ...

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 Ham ...

Wine Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are m ...

that allows one to run

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

software on Darwin. * SEDarwin is a port of

TrustedBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ope ...

mandatory access control In computer security, mandatory access control (MAC) refers to a type of access control by which the operating system or database constrains the ability of a ''subject'' or ''initiator'' to access or generally perform some sort of operation on a ...

framework and portions of the

SELinux Security-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including mandatory access controls (MAC). SELinux is a set of kernel modifications and user-space ...

framework to Darwin. It was incorporated into Mac OS X 10.5. * The Darbat project is an experimental port of Darwin to the

L4 microkernel family L4 is a family of second-generation microkernels, used to implement a variety of types of operating systems (OS), though mostly for Unix-like, ''Portable Operating System Interface'' (POSIX) compliant types. L4, like its predecessor microkernel ...

. It aims to be

binary compatible Binary-code compatibility (binary compatible or object-code-compatible) is a property of a computer system, meaning that it can run the same executable code, typically machine code for a general-purpose computer CPU, that another computer syste ...

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

and

ext3 ext3, or third extended filesystem, is a journaled file system that is commonly used by the Linux kernel. It used to be the default file system for many popular Linux distributions. Stephen Tweedie first revealed that he was working on ext ...

file systems.

References

External links

Darwin Releases
at

Apple Developer Connection Apple Developer (formerly Apple Developer Connection) is Apple Inc.'s website for software development tools, application programming interfaces (APIs), and technical resources. It contains resources to help software developers write software for ...

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