macOS is a series of running systems established by Apple for their Mac platform. macOS is the second-most commonly utilized operating system after Microsoft Windows. It initially ended up being publicly available in 1984 with the release of the Macintosh 128k.

The timeless Mac OS was originally written for the Motorola 68k architecture. The 68k architecture was utilized from 1984 to 1991, after which Apple transitioned to PowerPC. PowerPC would be utilized till the timeless Mac OS’s discontinuation in 2002. Classic Mac OS was based upon a basic kernel design, which eventually ended up being too restricted and crash-prone for applications. In action, Apple purchased NeXT and utilized NeXTSTEP as a base to develop Mac OS X. In 2006, Apple changed to Intel-based x86 processors in Macs. Support for PowerPC in Mac OS X was dropped in 2009.

At WWDC 2020, Apple stated that they would switch over to the Apple Silicon SoC in future Mac computer systems.

The Classic Mac OS can run standalone, and under Mac OS X utilizing the Classic system layer. Just particular versions of Mac OS 9 can run under the Classic system layer, and the layer itself was dropped after Mac OS X Tiger.

PearPC is a beneficial emulator that can run PowerPC builds of Mac OS X under Windows or other x86 operating systems. PCE and Mini vMac are able to run 68k builds of Mac OS, QEMU is likewise capable of running earlier PPC builds of MacOS, and VirtualBox and VMware Blend can run x86/64 builds of Mac OS X.

Classic [edit|edit source]

The original Macintosh System Software Application is based on the Lisa OS and UI concepts from Xerox PARC. It uses a monolithic architecture but lacks assistance for memory management, safeguarded memory, gain access to controls, and conflict-free extensions. Only one application at a time might be supported under System Software until variation 5 when MultiFinder was presented. In 1997, Apple rebranded the Macintosh System Software Application to Mac OS. Mac OS would continue to be developed up until the introduction of Mac OS X, after which Apple just provided minor updates to the timeless Mac OS. The final small updates were created to alleviate the shift to OS X. Carbon, an API introduced with Mac OS 8, works as the transitional API for traditional Mac OS and Mac OS X applications.

Name Versions Release date(s), Notes Codenames
System Software 1.x 1.0-1.1 h Released in January 1984-April 1984; uses the 68k architecture
System Software 2.x 2.0-2.1 Released in April 1985-September 1985
System Software 3.x 3.0-3.3 Released in January 1986-June 1987
System Software 4.x 4.0-4.1.1 Released in January 1987-July 1989
System Software 5.x 5.0-5.1 Launched in October 1987-February 1988
System Software 6.x 6.0-6.0.8.1 Launched in 1988-1992
Mac OS 7.x 7.0-7.6.1 Released in 1991-1997; first version to oficially run on PowerPC (included on version 7.1.2) Big Bang, Superbeta, Cube-E, Shuswap, Capone, Jirocho, Mozart, Kid of Buster, Unity, Zeus, Gory, Harmony, Ides.
Mac OS 8.x 8.0-8.6 Launched in 1997-1999; version 8.5 removed support for 68k Copland, Pace, Bride of Buster, Sequoia, Snowman, South Park, Allegro, Horatio, Veronica, Sarah.
Mac OS 9.x 9.0-9.2.2 Released in 1999-2001 Sonata, Minuet, Fortissimo, Moonlight, Limelight, LU1.

Mac OS X/ macOS [modify|modify source]

Mac OS X is the current incarnation of Mac OS. The very first version launched was Mac OS X Server in 1999. Unlike the traditional Mac OS, Mac OS X is based upon NeXTSTEP (OPENSTEP) and uses its structures and architectures. In 2016, Apple began to utilize the macOS moniker to brand Mac OS X along with their other os (watchOS, tvOS, iOS).

Name OS version Darwin variation Codename Notes
Mac OS X Server 1.x N/A Rhapsody 5.3 – 5.6 [note 1] Rhapsody Launched in March 1999
Mac OS X Public Beta N/A 1.2.1 Kodiak Launched in September 2000; presented the Aqua interface
Mac OS X Cheetah 10.0 1.3.1 Cheetah Launched in March 2001
Mac OS X Puma 10.1 1.4.1/ 5 Puma Launched in September 2001
Mac OS X Jaguar 10.2 6 Jaguar Launched in August 2002
Mac OS X Panther 10.3 7 Pinot Launched in October 2003
Mac OS X Tiger 10.4 8 Red Wine (PPC), Chardonay (Intel) Released in April 2005; initially variation to officially work on Intel (included 10.4.1)
Mac OS X Leopard 10.5 9 Chablis Released in October 2007
Mac OS X Snow Leopard 10.6 10 Snow Leopard Launched in August 2009; eliminates support for PowerPC Macs
Mac OS X Lion 10.7 11 Barolo Launched in July 2011; gets rid of assistance for PPC-only applications through Rosetta; removes assistance for x86 processors
OS X Mountain Lion 10.8 12 Zinfandel Launched in July 2012; removes the 32-bit kernel and 32-bit EFI bootloader
OS X Mavericks 10.9 13 Cabernet Launched in October 2013
OS X Yosemite 10.10 14 Syrah Released in October 2014; refreshed UI style
OS X El Capitan 10.11 15 Gala Released in September 2015
macOS Sierra 10.12 16 Fuji Released in September 2016; gets rid of support for non-SSE4 Intel CPUs
macOS High Sierra 10.13 17 Lobo Released in September 2017
macOS Mojave 10.14 18 Liberty Launched in September 2018
macOS Catalina 10.15 19 Catalina Released in October 2019; removes assistance for 32-bit applications
macOS Big Sur 11.x 20 Huge Sur Launched in November 2020; revitalized UI design; first variation to run on Apple Silicon
  1. ↑ Mac OS X Server 1.x is a direct descendant of the NeXTSTEP/OPENSTEP codebase and is not based on Darwin.