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Darwin (operating system)

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Title: Darwin (operating system)  
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Darwin (operating system)

Hexley the Platypus, a cartoon platypus standing, holding a trident and wearing a hat
Developer Apple Inc.
Written in C, C++
OS family Unix (BSD)
Working state Current
Source model Open source
Initial release November 15, 2000 (2000-11-15)
Latest release 14.0.0 / September 18, 2014 (2014-09-18)
Platforms PowerPC, x86, ARM
Kernel type Hybrid
Default user interface Command-line interface
License Mostly Apple Public Source License, with proprietary drivers[1]
Official website .com.appleopensource
Simplified history of Unix-like operating systems.

Darwin is an open source Unix-like computer operating system released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, and other free software projects.

Darwin forms the core set of components upon which OS X and iOS are based. It is mostly POSIX compatible, but has never, by itself, been certified as being compatible with any version of POSIX. (OS X, since Leopard, has been certified as compatible with the Single UNIX Specification version 3 (SUSv3).[2][3][4])


  • History 1
  • Design 2
    • Kernel 2.1
    • Hardware and software support 2.2
  • License 3
  • Mascot 4
  • Release history 5
  • Derived projects 6
    • OpenDarwin 6.1
    • PureDarwin 6.2
    • Other 6.3
  • See also 7
  • References 8
  • External links 9


Darwin's heritage began with NeXT's NeXTSTEP operating system (later 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 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 computers as a standalone operating system. Minor updates were released as packages that were installed separately. Darwin is now only available as source code,[5] except for the ARM variant, which has not been released in any form separately from iOS. However, the older versions of Darwin are still available in binary form,[6] and a hobbyist developer winocm took the official Darwin source code and ported it to ARM.[7]



Darwin is built around XNU, a hybrid kernel that combines the Mach 3 microkernel, various elements of BSD (including the process model, network stack, and virtual file system),[8] and an object-oriented device driver API called I/O Kit.[9] The hybrid kernel design compromises between the flexibility of a microkernel and the performance of a monolithic kernel.

Hardware and software support

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, as well as the 32-bit ARM processors used in the iPhone, iPod Touch, iPad and the second and third generation Apple TV. An open-source port of the XNU kernel exists which supports Darwin on Intel and AMD x86 platforms not officially supported by Apple, although it does not appear to have been updated since 2009.[10] An open-source port of the XNU kernel also exists for ARM platforms.[11] 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 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 Mac OS X, 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 Mac OS X, 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 is approved as a free software license by the Free Software Foundation (FSF). Previous versions had been released under an earlier version of the APSL license, which did not meet the FSF's definition of free software, although it met 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. 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. Hexley was designed by Jon Hooper. Apple does not sanction Hexley as a logo for Darwin.[12]

The name Hexley is an accidental misspelling of the last name of Thomas Henry Huxley, a 19th-century English biologist who was a well-known champion of Charles Darwin's theory of evolution (nicknamed "Darwin's bulldog"). The name was chosen under the misunderstanding that he was an assistant of Darwin, rather than a prominent biologist in his own right. By the time the spelling mistake had been discovered, it was deemed too late to change, and the erroneous name was kept.[13]

Release history

This is a table of major Darwin releases with their dates of release and their corresponding Mac OS X releases.[14] Note that the corresponding Mac OS X release may have been released on a different date; refer to the Mac OS X pages for those dates.

Version Date Corresponding releases Notes
0.1 March 16, 1999 Mac OS X DP 0.1 is contrived (for sorting and identification) as this identified itself simply as Mac OS 10.0
0.2 November 10, 1999 Mac OS X DP2
1.0 February 2000 Mac OS X DP3
1.1 April 5, 2000 Mac OS X DP4
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 First commercial release of Darwin
1.3.1 June 21, 2001 Mac OS X v10.0.4 All releases of "Cheetah" (10.0–10.0.4) had the same version of Darwin
1.4.1 October 2, 2001 Mac OS X v10.1 Performance improvements to "boot time, real-time threads, thread management, cache flushing, and preemption handling," support for SMB network file system, Wget replaced with cURL.[15]
5.1 November 12, 2001 Mac OS X v10.1.1 Change in numbering scheme to match Mac OS X build numbering scheme (e.g., Mac OS X v10.1 contains build numbers starting with 5 so Mac OS X v10.1.1 is now based on Darwin 5.1; i.e., 10.1 means 5 so 10.1.1 means 5.1, etc.)
5.5 June 5, 2002 Mac OS X v10.1.5 Last release of "Puma"
6.0.1 September 23, 2002 Mac OS X v10.2 (Darwin 6.0.2) GCC upgraded from 2 to 3.1, IPv6 and IPSec support, mDNSResponder service discovery daemon (Rendezvous), addition of CUPS, Ruby, and Python, journaling support in HFS+ (Darwin 6.2), application profiles ("pre-heat files") for faster program launching.[16]
6.8 October 3, 2003 Mac OS X v10.2.8 Last release of "Jaguar"
7.0 October 24, 2003 Mac OS X v10.3 BSD layer synchronized with FreeBSD 5, automatic file defragmentation, hot-file clustering, and optional case sensitivity in HFS+, bash instead of tcsh as default shell, read-only NTFS support (Darwin 7.9).[17]
7.9 April 15, 2005 Mac OS X v10.3.9 Last release of "Panther"
8.0 April 29, 2005 Mac OS X v10.4
Mac OS X for Apple TV (Darwin 8.8.2)
Stable kernel programming interface, finer-grained kernel locking, 64-bit BSD layer, launchd service management framework, extended file attributes, access control lists, commands such as cp and mv updated to preserve extended attributes and resource forks.[18]
8.11 November 14, 2007 Mac OS X v10.4.11 Last release of "Tiger"
9.0 October 26, 2007 iPhone OS 1 (Darwin 9.0.0d1)
Mac OS X v10.5
Full POSIX compliance, improved hierarchical process scheduling model, dynamically allocated swap files, dynamic resource limits (for files and processes), process sandboxing, address space layout randomization, DTrace tracing framework, file system events daemon, directory hard links, Apache 1.3 and PHP 4 updated to Apache 2.2 and PHP 5, read-only ZFS support.[19]
9.8 August 5, 2009 Mac OS X v10.5.8 Last release of "Leopard"
10.0 August 28, 2009 Mac OS X v10.6
iOS 4
End of official support for PowerPC architecture (although several fat binaries, such as Kernel, still contain PPC images); 64-bit kernel and drivers, libdispatch task parallelization framework, OpenCL heterogeneous computing framework, support for blocks in C, transparent file compression in HFS+.[20]
10.8 June 23, 2011 Mac OS X v10.6.8 Last release of "Snow Leopard"
11.0.0 July 20, 2011 Mac OS X v10.7

iOS 5[21]

XNU no longer supports PPC binaries (fat binary only for i386, x86_64). XNU requires an x86_64 processor. Improved sandboxing of applications
11.4.2 October 4, 2012 Mac OS X v10.7.5 Last release of "Lion", supplemental
12.0.0 February 16, 2012 OS X v10.8 Code named "Mountain Lion"; the word "Mac" has been dropped from the name
12.5.0 September 12, 2013 OS X v10.8.5 Last release of "Mountain Lion"
13.0.0 June 11, 2013 OS X v10.9
iOS 6
OS X v. 10.9 is code named "Mavericks"
14.0.0 September 18, 2014 iOS 7, iOS 8 and OS X v10.10 OS X v. 10.10 is code named "Yosemite"

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 Mac OS X, every version has a unique beginning build number, which identifies what whole version of Mac OS X 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). The point release number in the Darwin version is always the same as the second point number in the Mac OS X version. 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.[22]

The command uname -r in Terminal will show the Darwin version number, and the command uname -v will show the XNU build version string, which includes the Darwin version number.

Derived projects

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


GNOME running on OpenDarwin.

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 supposedly benefited from being given complete control over its own operating system, which could then be used in free software distributions such as GNU-Darwin.[23]

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."[24] The last stable release was version 7.2.1, released on July 16, 2004.


In 2007, the PureDarwin project was launched to continue where OpenDarwin left off, and is currently working to produce a release based on Darwin 11. There is a version available based on Darwin 10.5.8. This release has X11, DTrace, and ZFS.[25] PureDarwin nano is another release of PureDarwin that is supposed to be minimalistic.


  • MacPorts (formerly DarwinPorts), Fink, and Homebrew are well known 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, and Portage—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.
  • The Darwine project is a port of Wine that allows one to run Microsoft Windows software on Darwin.
  • SEDarwin is a port of TrustedBSD mandatory access control framework and portions of the SELinux framework to Darwin.[26] It was incorporated into Mac OS X 10.5.[27]
  • The Darbat project is an experimental port of Darwin to the L4 microkernel family. It aims to be binary compatible with existing Darwin binaries.[28]
  • There are various projects that focus on driver support: e.g., wireless drivers,[29][30] wired NIC drivers[31][32][33] modem drivers,[34] card readers,[35] and the ext2 and ext3 file systems.[36][37]

See also


  1. ^ "Binary Drivers required for PureDarwin". Retrieved July 20, 2009. 
  2. ^ "Mac OS X Leopard - Technology - UNIX". Leopard Technology Overview. Apple Inc. Archived from the original on December 27, 2008. 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. 
  3. ^ The Open Group (May 18, 2007). "Mac OS X Version 10.5 Leopard on Intel-based Macintosh computers certification". Retrieved February 11, 2013. 
  4. ^ The Open Group (July 10, 2012). "Mac OS X Version 10.8 Mountain Lion on Intel-based Macintosh computers certification". Retrieved February 11, 2013. 
  5. ^ Hubbard, Jordan (October 31, 2007). "Re: Darwin 9.0 Source Code Available."". darwinos-users mailing list. Retrieved November 27, 2007.
  6. ^ /iso/
  7. ^ /xnu/darwin-on-arm.comgithub
  8. ^ "Mac Technology Overview: Kernel and Device Drivers Layer".  
  9. ^ Singh, Amit (January 7, 2004). "XNU: The Kernel". Retrieved February 11, 2013. 
  10. ^ "Voodoo XNU Kernel Source".  Requires an Apache SVN client.
  11. ^ "XNU on ARMv7". 
  12. ^ Hooper, Jon. "Homepage of Hexley the DarwinOS mascot". Retrieved November 30, 2008. 
  13. ^ Hooper, Jon. "Hexley Darwin Mascot History". Retrieved November 30, 2008. 
  14. ^ "Open Source Releases".  
  15. ^ "Technical Note TN2029: Mac OS X v10.1".  
  16. ^ Siracusa, John (September 5, 2002). "Mac OS X 10.2 Jaguar".  
  17. ^ Siracusa, John (November 9, 2003). "Mac OS X 10.3 Panther".  
  18. ^ Siracusa, John (April 28, 2005). "Mac OS X 10.4 Tiger".  
  19. ^ Siracusa, John (October 28, 2007). "Mac OS X 10.5 Leopard: the Ars Technica review".  
  20. ^ Siracusa, John (August 31, 2009). "Mac OS X 10.6 Snow Leopard: the Ars Technica review".  
  21. ^ As found on a jailbroken iPhone 4S
  22. ^ Prabhakar, Ernie (November 9, 2001). "Darwin Version - New Scheme in Software Update 1". darwin-development mailing list. Retrieved June 2, 2008.
  23. ^ "OpenDarwin". OpenDarwin Project. Archived from the original on January 6, 2006. 
  24. ^ OpenDarwin Core Team and Administrators (July 25, 2006). "OpenDarwin Shutting Down". OpenDarwin Project. Archived from the original on August 4, 2006. 
  25. ^ "PureDarwin Download Page". 
  26. ^ "Security Enhanced Darwin". SEDarwin. January 22, 2007. Archived from the original on October 5, 2011. 
  27. ^ "What's New In Mac OS X: Mac OS X v10.5". Mac OS X Reference Library. Apple Inc. November 13, 2009. Archived from the original on December 8, 2009. 
  28. ^ " | ERTOS | NICTA". May 9, 2007. Retrieved July 12, 2010. 
  29. ^ yuriwho (May 5, 2002). "WirelessDriver Home Page". Retrieved July 12, 2010. 
  30. ^ "iwi2200 Darwin".  
  31. ^ "Port BSD tulip driver(s) to Darwin OS | Download Port BSD tulip driver(s) to Darwin OS software for free at". Retrieved July 12, 2010. 
  32. ^ "RealTek network driver for Mac OS X/Darwin".   Project inactive since March 15, 2006.
  33. ^ fansui, et al. (August 1, 2007). "RTL8150LMEthernet". SourceForge. Retrieved June 13, 2010. 
  34. ^ "ZyXEL Modem Drivers for OS X/Darwin | Download ZyXEL Modem Drivers for OS X/Darwin software for free at". May 14, 2002. Retrieved July 12, 2010. 
  35. ^ "Mac OS X PC Card ATA Driver". December 20, 2001. Retrieved July 12, 2010. 
  36. ^ "Mac OS X Ext2 Filesystem | Download Mac OS X Ext2 Filesystem software for free at". October 14, 2002. Retrieved July 12, 2010. 
  37. ^ "ext2 filesystem in user space".  

External links

  • Darwin Releases at Apple Developer Connection
  • Darwin Build Number List
  • Darwin Source Repository at SourceForge
  • Hexley, the Darwin mascot
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