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Mac operating systems

From Wikipedia, the free encyclopedia

Two major families of Mac operating systems were developed by Apple Inc.

In 1984, Apple debuted the operating system that is now known as the "Classic" Mac OS with its release of the original Macintosh System Software. The system, rebranded "Mac OS" in 1997, was pre-installed on every Macintosh until 2002 and offered on Macintosh clones for a short time in the 1990s. It was noted for its ease of use, and also criticized for its lack of modern technologies compared to its competitors.[1][2]

The current Mac operating system is macOS, originally named "Mac OS X" until 2012 and then "OS X" until 2016.[3] It was developed between 1997 and 2001 after Apple's purchase of NeXT. It brought an entirely new architecture based on NeXTSTEP, a Unix system, that eliminated many of the technical challenges that the classic Mac OS faced, such as problems with memory management. The current macOS is pre-installed with every Mac and receives a major update annually.[4] It is the basis of Apple's current system software for its other devices – iOS, iPadOS, watchOS, and tvOS.[5]

Prior to the introduction of Mac OS X, Apple experimented with several other concepts, releasing different products designed to bring the Macintosh interface or applications to Unix-like systems or vice versa, A/UX, MAE, and MkLinux. Apple's effort to expand upon and develop a replacement for its classic Mac OS in the 1990s led to a few cancelled projects, code named Star Trek, Taligent, and Copland.

Although the classic Mac OS and macOS (Mac OS X) have different architectures, they share a common set of GUI principles, including a menu bar across the top of the screen; the Finder shell, featuring a desktop metaphor that represents files and applications using icons and relates concepts like directories and file deletion to real-world objects like folders and a trash can; and overlapping windows for multitasking.

Before the arrival of the Macintosh in 1984, Apple's history of operating systems began with its Apple II series computers in 1977, which ran Apple DOS, ProDOS, and later GS/OS; the Apple III in 1980, which ran Apple SOS; and the Apple Lisa in 1983, which ran Lisa OS and later MacWorks XL, a Macintosh emulator. Apple also developed the Newton OS for its Newton personal digital assistant from 1993 to 1997.

In recent years, Apple has also launched several new operating systems based on the core of macOS, including iOS in 2007 for its iPhone, iPad, and iPod Touch mobile devices and in 2017 for its HomePod smart speakers; watchOS in 2015 for the Apple Watch; tvOS in 2015 for the Apple TV set-top box.

Classic Mac OS[edit]

Mac OS 9, released in 1999

The "classic" Mac OS is the original Macintosh operating system that was introduced in 1984 alongside the first Macintosh and remained in primary use on Macs until the introduction of Mac OS X in 2001.[6][7]

Apple released the original Macintosh on January 24, 1984; its early system software was partially based on the Lisa OS, and inspired by the Alto computer, which former Apple CEO Steve Jobs previewed at Xerox PARC.[6] It was originally named "System Software", or simply "System"; Apple rebranded it as "Mac OS" in 1996 due in part to its Macintosh clone program that ended a year later.[8]

Classic Mac OS is characterized by its monolithic design. Initial versions of the System Software run one application at a time. System 5 introduced cooperative multitasking. System 7 supports 32-bit memory addressing and virtual memory, allowing larger programs. Later updates to the System 7 enable the transition to the PowerPC architecture. The system was considered user-friendly, but its architectural limitations were critiqued, such as limited memory management, lack of protected memory and access controls, and susceptibility to conflicts among extensions.[2]


The text-only logo for Classic Mac OS starting with Mac OS 7.6, released in 1997

Nine major versions of the classic Mac OS were released. The name "Classic" that now signifies the system as a whole is a reference to a compatibility layer that helped ease the transition to Mac OS X.[9]

Mac OS X / OS X / macOS[edit]

macOS Big Sur, released in 2020, introduced the current design iteration of macOS.

macOS (originally named "Mac OS X" until 2012 and then "OS X" until 2016)[10] is the current Mac operating system that officially succeeded the classic Mac OS in 2001.

The system was originally marketed as simply "version 10" of Mac OS, but it has a history that is largely independent of the classic Mac OS. It is a Unix-based operating system[11][12] built on NeXTSTEP and other technology developed at NeXT from the late 1980s until early 1997, when Apple purchased the company and its CEO Steve Jobs returned to Apple.[13] Precursors to the original release of Mac OS X include OPENSTEP, Apple's Rhapsody project, and the Mac OS X Public Beta.

macOS makes use of the BSD codebase and the XNU kernel,[14] and its core set of components is based upon Apple's open source Darwin operating system.

macOS is the basis for some of Apple's other operating systems, including iPhone OS/iOS, iPadOS, watchOS, tvOS and visionOS.


The "X" logo for Mac OS X versions 10.0 "Cheetah" and 10.1 "Puma", released in 2001


The first version of the system was released on March 24, 2001, supporting the Aqua user interface. Since then, several more versions adding newer features and technologies have been released. Since 2011, new releases have been offered on an yearly basis.[4]

  • Mac OS X 10.0 – code named "Cheetah", released to end users on Saturday, March 24, 2001
  • Mac OS X 10.1 – code named "Puma", released to end users on Tuesday, September 25, 2001
  • Mac OS X Jaguar – version 10.2, released to end users on Friday, August 23, 2002
  • Mac OS X Panther – version 10.3, released to end users on Friday, October 24, 2003
  • Mac OS X Tiger – version 10.4, released to end users on Friday, April 29, 2005
  • Mac OS X Leopard – version 10.5, released to end users on Friday, October 26, 2007
  • Mac OS X Snow Leopard – version 10.6, publicly unveiled on Monday, June 8, 2009
  • Mac OS X Lion – version 10.7, released to end users on Wednesday, July 20, 2011
  • OS X Mountain Lion – version 10.8, released to end users on Wednesday, July 25, 2012
  • OS X Mavericks – version 10.9, released to end users on Tuesday, October 22, 2013
  • OS X Yosemite – version 10.10, released to end users on Thursday, October 16, 2014
  • OS X El Capitan – version 10.11, released to end users on Wednesday, September 30, 2015
  • macOS Sierra – version 10.12, released to end users on Tuesday, September 20, 2016
  • macOS High Sierra – version 10.13, released to end users on Monday, September 25, 2017
  • macOS Mojave – version 10.14, released to end users on Monday, September 24, 2018
  • macOS Catalina – version 10.15, released to end users on Monday, October 7, 2019
  • macOS Big Sur – version 11, released to end users on Thursday, November 12, 2020
  • macOS Monterey – version 12, released to end users on Monday, October 25, 2021
  • macOS Ventura – version 13, released to end users on Monday, October 24, 2022
  • macOS Sonoma - version 14, released to end users on Tuesday, September 26, 2023

As of 2020, only one version of macOS was never publicly released, with its version number updated during development. 10.16 was updated to 11.0 in the third beta; the third beta version of macOS Big Sur was 11.0 Beta 3 instead of 10.16 Beta 3.


An early server computing version of the system was released in 1999 as a technology preview. It was followed by several more official server-based releases. Server functionality has instead been offered as an add-on for the desktop system since 2011.[15]

Other projects[edit]



The Apple Real-time Operating System Environment (A/ROSE) was a small embedded operating system which ran on the Macintosh Coprocessor Platform, an expansion card for the Macintosh. The idea was to offer a single "overdesigned" hardware platform on which third-party vendors could build practically any product, reducing the otherwise heavy workload of developing a NuBus-based expansion card. The first version of the system was ready for use in February 1988.[16]


In 1988, Apple released its first UNIX-based OS, A/UX, which was a UNIX operating system with the Mac OS look and feel. It was not very competitive for its time, due in part to the crowded UNIX market and Macintosh hardware lacking high-end design features present on workstation-class computers. A/UX had most of its success in sales to the U.S. government, where POSIX compliance was a requirement that Mac OS could not meet.[17]


The Macintosh Application Environment (MAE) was a software package introduced by Apple in 1994 that allowed users of certain Unix-based computer workstations to run Apple Macintosh application software. MAE used the X Window System to emulate a Macintosh Finder-style graphical user interface. The last version, MAE 3.0, was compatible with System 7.5.3. MAE was available for Sun Microsystems SPARCstation and Hewlett-Packard systems. It was discontinued on May 14, 1998.[18]


Announced at the 1996 Worldwide Developers Conference (WWDC), MkLinux is an open source operating system that was started by the OSF Research Institute and Apple in February 1996 to port Linux to the PowerPC platform, and thus Macintosh computers. In mid 1998, the community-led MkLinux Developers Association took over development of the operating system. MkLinux is short for "Microkernel Linux," which refers to the project's adaptation of the Linux kernel to run as a server hosted atop the Mach microkernel. MkLinux is based on version 3.0 of Mach.[19]

Cancelled projects[edit]

Star Trek[edit]

Star Trek (as in "to boldly go where no Mac has gone before") was a relatively unknown secret prototype beginning in 1992, whose goal was to create a version of the classic Mac OS that would run on Intel-compatible x86 personal computers. In partnership with Apple and with support from Intel, the project was instigated by Novell, which was looking to integrate its DR-DOS with the Mac OS GUI as a mutual response to the monopoly of Microsoft's Windows 3.0 and MS-DOS. A team consisting of four from Apple and four from Novell was able to get the Macintosh Finder and some basic applications such as QuickTime, running smoothly on the x86 architecture. The project was canceled a year later in early 1993, but some of the code was later reused when porting the Mac OS to PowerPC.[20][21]


Taligent (a portmanteau of "talent" and "intelligent") was the name of an object-oriented operating system and the company dedicated to producing it. Started as a project within Apple to provide a replacement for the classic Mac OS, it was later spun off into a joint venture with IBM as part of the AIM alliance, with the purpose of building a competing platform to Microsoft Cairo and NeXTSTEP. The development process never worked, and Taligent is often cited as an example of a project death march. Apple pulled out of the project in 1995 before the code had been delivered.[22]


Copland was a project at Apple to create an updated version of the classic Mac OS. It was to have introduced protected memory, preemptive multitasking and a number of new underlying operating system features, yet still be compatible with existing Mac software. As originally planned, a follow-up release known as "Gershwin" would add multithreading and other advanced features. New features were added more rapidly than they could be completed, and the completion date slipped into the future with no sign of a release. In 1996, Apple decided to cancel the project outright and find a suitable third-party system to replace it. Copland development ended in August 1996, and in December 1996, Apple announced that it was buying NeXT for its NeXTSTEP operating system.[23]


Timeline of Mac operating systems
ARM architecture familyx86PowerPC68kMacBook Air (Apple silicon)iMac ProRetina MacBook ProMacBook AirApple–Intel architecturePower Mac G5Power Mac G4iMac G3Power MacintoshMacintosh QuadraMacintosh PortableMacintosh SE/30Macintosh IIMacintosh PlusMacintosh 128KmacOS SonomamacOS VenturamacOS MontereymacOS Big SurmacOS CatalinamacOS MojavemacOS High SierramacOS SierraOS X El CapitanOS X YosemiteOS X MavericksOS X Mountain LionMac OS X LionMac OS X Snow LeopardMac OS X LeopardMac OS X TigerMac OS X PantherMac OS X 10.2Mac OS X 10.1Mac OS X 10.0Mac OS X Server 1.0Mac OS X Public BetaA/UXA/UXA/UXMacWorks XLMacWorks XLSun RemarketingMacWorks XLMac OS 9Mac OS 9Mac OS 9Mac OS 8Mac OS 8Mac OS 8Mac OS 8System 7System 7System 7System 7System 6Classic Mac OSClassic Mac OSClassic Mac OSClassic Mac OSSystem 1Finder (software)Finder (software)Finder (software)Finder (software)Finder (software)Finder (software)Finder (software)

See also[edit]


  1. ^ Gruber, John (January 21, 2009). "Three things OS X could learn from the Classic Mac OS". Macworld. Archived from the original on September 24, 2016. Retrieved September 13, 2016.
  2. ^ a b Hertzfeld, Andy. "The Original Macintosh: Mea Culpa". folklore.org. Archived from the original on June 19, 2010. Retrieved May 10, 2010.
  3. ^ Siracusa, John (March 24, 2006). "Five years of Mac OS X". Ars Technica. Condé Nast Digital. Archived from the original on June 25, 2009. Retrieved April 15, 2009. Even Steve Jobs still says "ecks" instead of "ten" sometimes.
  4. ^ a b Gruber, John. "Mountain Lion". Daring Fireball. Archived from the original on August 11, 2015. Retrieved August 15, 2015.
  5. ^ Honan, Matthew (January 9, 2007). "Apple unveils iPhone". Macworld. Archived from the original on April 15, 2008. Retrieved January 16, 2010.
  6. ^ a b Linzmayer, Owen W. (2004). Apple Confidential 2.0. No Starch Press. Archived from the original on November 13, 2016. Retrieved October 1, 2016.
  7. ^ "The Macintosh Product Introduction Plan". Stanford University Libraries & Academic Information Resources. Stanford University. Archived from the original on July 21, 2010.
  8. ^ Gruman, Galen (November 1997). "Why Apple Pulled the Plug". Macworld. Vol. 14, no. 11. pp. 31–36.
  9. ^ "A Brief History of the Classic Mac OS". Low End Mac. Archived from the original on October 5, 2016. Retrieved October 1, 2016.
  10. ^ "What is an operating system (OS)?". Apple Inc. July 15, 2004. Archived from the original on July 22, 2010. Retrieved September 6, 2014.
  11. ^ "Mac OS X and Unix" (PDF). Apple Inc. Archived from the original (PDF) on May 30, 2009. Retrieved February 5, 2016.
  12. ^ "macOS version 10.12 Sierra on Intel-based Mac computers". The Open Group. Archived from the original on October 2, 2016. Retrieved September 29, 2016.
  13. ^ "Apple Computer, Inc. Agrees to Acquire NeXT Software Inc". Apple Computer. December 20, 1996. Archived from the original on January 16, 1999.
  14. ^ "Mac OS X: What is BSD?". Apple Inc. Archived from the original on February 19, 2013. Retrieved October 25, 2012.
  15. ^ "Apple Releases Developer Preview of Mac OS X Lion" (Press release). Apple Inc. February 24, 2011. Archived from the original on October 13, 2019. Retrieved October 13, 2019.
  16. ^ "Inside the Macintosh Coprocessor Platform and A/ROSE". Archived from the original on October 15, 2016. Retrieved October 1, 2016.
  17. ^ Crabb, Don (August 10, 1992). "Apple finally gets Unix right with A/UX 3.0". InfoWorld. pp. 68–69. Archived from the original on August 1, 2016. Retrieved October 1, 2016.
  18. ^ "MAE screenshots". Archived from the original on January 24, 2014. Retrieved March 4, 2015.
  19. ^ Barbou des Places, François; Stephen, Nick; Reynolds, Franklin D. (January 12, 1996). "Linux on the OSF Mach3 microkernel". Grenoble and Cambridge: OSF Research Institute. Archived from the original on February 11, 2012. Retrieved April 4, 2013.
  20. ^ Hormby, Tom (2005). "Star Trek: Apple's First Mac OS on Intel Project". Low End Mac. Archived from the original on November 2, 2015. Retrieved November 10, 2015.
  21. ^ Linzmayer, Owen W. (1999). Apple Confidential. San Francisco, CA: No Starch Press. ISBN 9781886411289. OCLC 245921029. Archived from the original on September 20, 2019. Retrieved May 29, 2017.
  22. ^ "Apple surrenders the Pink (to Microsoft) Archived August 10, 2017, at the Wayback Machine", The Register, October 3, 2008.
  23. ^ Widman, Jake (October 9, 2008). "Lessons Learned: IT's Biggest Project Failures". PCWorld. Archived from the original on November 5, 2012. Retrieved October 23, 2012.

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