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<h2 id="classic-mac-os">Classic Mac OS</h2> <p class="note">Main article: <a href="/facts/Classic_Mac_OS/I5fQq44K">Classic Mac OS</a></p> <p>The <a href="/facts/Classic_Mac_OS/I5fQq44K">classic Mac OS</a> is the original Macintosh operating system introduced in 1984 alongside the <a href="/facts/Macintosh_128K/oXlQGVpX">first Macintosh</a> and remained in primary use on Macs until <a href="/facts/Mac_OS_X/Y93vVpTm">Mac OS X</a> in 2001.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a><a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> </p><p>Apple released the <a href="/facts/Macintosh_128K/oXlQGVpX">original Macintosh</a> on January 24, 1984; its <a href="/facts/System_1/I0cCfckN">early system software</a> is partially based on <a href="/facts/Lisa_OS/PJpJhNRK">Lisa OS</a>, and inspired by the <a href="/facts/Xerox_Alto/6pjFTD0A">Alto</a> computer, which former Apple CEO <a href="/facts/Steve_Jobs/fQpja1hx">Steve Jobs</a> previewed at <a href="/facts/PARC_(company)/fh2Su0k9">Xerox PARC</a>.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> It was originally named "System Software", or simply "System"; Apple rebranded it as "Mac OS" in 1996 due in part to its <a href="/facts/Macintosh_clone/bP9eUlRd">Macintosh clone</a> program that ended one year later.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p><p>Classic Mac OS is characterized by its <a href="/facts/Monolithic_system/2Sa3Rwer">monolithic</a> design. Initial versions of the System Software run one application at a time. System 5 introduced <a href="/facts/Cooperative_multitasking/svrQ2DMM">cooperative multitasking</a>. System 7 supports <a href="/facts/32-bit/TDMVce8s">32-bit</a> <a href="/facts/Memory_address/7EsUmbea">memory addressing</a> and <a href="/facts/Virtual_memory/Lw2GemF5">virtual memory</a>, allowing larger programs. Later updates to the System 7 enable the transition to the <a href="/facts/PowerPC/DqmM9y50">PowerPC</a> architecture. The system was considered <a href="/facts/Usability/zuAnqu9Q">user-friendly</a>, but its architectural limitations were critiqued, such as limited <a href="/facts/Classic_Mac_OS_memory_management/Cek0IhWn">memory management</a>, lack of <a href="/facts/Protected_memory/3zDwN2SG">protected memory</a> and <a href="/facts/Computer_access_control/Uu8f7vmX">access controls</a>, and susceptibility to conflicts among <a href="/facts/Extension_(Mac_OS)/bDjfLGKj">extensions</a>.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p> <h3>Releases</h3> <p>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 href="/facts/List_of_macOS_components/7uDAhFUz">a compatibility layer</a> that helped ease the transition to <a href="/facts/MacOS/Y93vVpTm">Mac OS X</a>.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p> <ul><li><a href="/facts/System_1/I0cCfckN">Macintosh System Software</a> – "System 1", released in 1984</li> <li><a href="/facts/Classic_Mac_OS/I5fQq44K">System Software 2, 3, and 4</a> – released between 1985 and 1987</li> <li><a href="/facts/Classic_Mac_OS/I5fQq44K">System Software 5</a> – released in 1987</li> <li><a href="/facts/System_6/5hKYcxEV">System Software 6</a> – released in 1988</li> <li><a href="/facts/System_7/IwLKo2sX">System 7 / Mac OS 7.6</a> – released in 1991</li> <li><a href="/facts/Mac_OS_8/Vde5S5hl">Mac OS 8</a> – released in 1997</li> <li><a href="/facts/Mac_OS_9/33QM3VqV">Mac OS 9</a> – final major version, released in 1999</li></ul> <h2 id="mac-os-x-os-x-and-macos">Mac OS X, OS X, and macOS</h2> <p class="note">Main article: <a href="/facts/MacOS/Y93vVpTm">macOS</a></p> <p>The system was launched as Mac OS X, renamed OS X from 2012—2016,<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> and then renamed <a href="/facts/MacOS/Y93vVpTm">macOS</a> as the current Mac operating system that officially succeeded the classic Mac OS in 2001. </p><p>The system was originally marketed as simply "version 10" of Mac OS, but it has <a href="/facts/History_of_macOS/qR6fo5mj">a history that is largely independent</a> of the classic Mac OS. It is a <a href="/facts/Unix/0pNL2seI">Unix</a>-based operating system<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a><a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> built on <a href="/facts/NeXTSTEP/eL0bymga">NeXTSTEP</a> and other <a href="/facts/NeXT/qcCmhJl3">NeXT</a> technology from the late 1980s until early 1997, when Apple purchased the company and its CEO <a href="/facts/Steve_Jobs/fQpja1hx">Steve Jobs</a> returned to Apple.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> Precursors to Mac OS X include <a href="/facts/OPENSTEP/RTKQxPR1">OPENSTEP</a>, Apple's <a href="/facts/Rhapsody_(operating_system)/KYa1NJIl">Rhapsody</a> project, and the <a href="/facts/Mac_OS_X_Public_Beta/YhCaCyIj">Mac OS X Public Beta</a>. </p><p>macOS is based on Apple's <a href="/facts/Open-source_software/HzTaB8E9">open source</a> <a href="/facts/Darwin_(operating_system)/DogI3ptd">Darwin operating system</a>, which is based on the <a href="/facts/XNU/dUCpExf0">XNU</a> kernel and <a href="/facts/BSD/XQKcURrh">BSD</a>.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a> </p><p>macOS is the basis for some of Apple's other operating systems, including <a href="/facts/IPhone_OS/mK5cggH5">iPhone OS</a>/<a href="/facts/IOS/mK5cggH5">iOS</a>, <a href="/facts/IPadOS/fClrmH7D">iPadOS</a>, <a href="/facts/WatchOS/zH1fkn2R">watchOS</a>, <a href="/facts/TvOS/jDMqvvfI">tvOS</a>, and <a href="/facts/Apple_Vision_Pro/N7Tkaj68">visionOS</a>. </p> <h3>Releases</h3> <h4>Desktop</h4> <p>The first version of the system was released on March 24, 2001, supporting the <a href="/facts/Aqua_user_interface/JUUtQf3F">Aqua user interface</a>. Since then, several more versions adding newer features and technologies have been released. Since 2011, new releases have been offered annually.<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> </p> <ul><li><a href="/facts/Mac_OS_X_10.0/twuQ9J75">Mac OS X 10.0</a> – codenamed "Cheetah", released Saturday, March 24, 2001</li> <li><a href="/facts/Mac_OS_X_10.1/vfcIENRm">Mac OS X 10.1</a> – codenamed "Puma", released Tuesday, September 25, 2001</li> <li><a href="/facts/Mac_OS_X_Jaguar/HboYAjXy">Mac OS X Jaguar</a> – version 10.2, released Friday, August 23, 2002</li> <li><a href="/facts/Mac_OS_X_Panther/lDrnzKAe">Mac OS X Panther</a> – version 10.3, released Friday, October 24, 2003</li> <li><a href="/facts/Mac_OS_X_Tiger/q6vKCpvq">Mac OS X Tiger</a> – version 10.4, released Friday, April 29, 2005</li> <li><a href="/facts/Mac_OS_X_Leopard/UmXw4H5x">Mac OS X Leopard</a> – version 10.5, released Friday, October 26, 2007</li> <li><a href="/facts/Mac_OS_X_Snow_Leopard/GGNogRTe">Mac OS X Snow Leopard</a> – version 10.6, publicly unveiled on Monday, June 8, 2009</li> <li><a href="/facts/Mac_OS_X_Lion/CHyxXg8X">Mac OS X Lion</a> – version 10.7, released Wednesday, July 20, 2011</li> <li><a href="/facts/OS_X_Mountain_Lion/GIu66667">OS X Mountain Lion</a> – version 10.8, released Wednesday, July 25, 2012</li> <li><a href="/facts/OS_X_Mavericks/5xavJXqv">OS X Mavericks</a> – version 10.9, released Tuesday, October 22, 2013</li> <li><a href="/facts/OS_X_Yosemite/nUzgd9Il">OS X Yosemite</a> – version 10.10, released Thursday, October 16, 2014</li> <li><a href="/facts/OS_X_El_Capitan/4NAIbG7c">OS X El Capitan</a> – version 10.11, released Wednesday, September 30, 2015</li> <li><a href="/facts/MacOS_Sierra/jV5ocHbo">macOS Sierra</a> – version 10.12, released Tuesday, September 20, 2016</li> <li><a href="/facts/MacOS_High_Sierra/RXfrv9pf">macOS High Sierra</a> – version 10.13, released Monday, September 25, 2017</li> <li><a href="/facts/MacOS_Mojave/QCehr08a">macOS Mojave</a> – version 10.14, released Monday, September 24, 2018</li> <li><a href="/facts/MacOS_Catalina/B2RE5fGd">macOS Catalina</a> – version 10.15, released Monday, October 7, 2019</li> <li><a href="/facts/MacOS_Big_Sur/RV8pCK4d">macOS Big Sur</a> – version 11, released Thursday, November 12, 2020</li> <li><a href="/facts/MacOS_Monterey/cwXg0zIR">macOS Monterey</a> – version 12, released Monday, October 25, 2021</li> <li><a href="/facts/MacOS_Ventura/6JzKPJML">macOS Ventura</a> – version 13, released Monday, October 24, 2022</li> <li><a href="/facts/MacOS_Sonoma/FCrCcpx0">macOS Sonoma</a> - version 14, released Tuesday, September 26, 2023</li> <li><a href="/facts/MacOS_Sequoia/aMftEP5V">macOS Sequoia</a> - version 15, released Monday, September 16, 2024</li></ul> <p>macOS 10.16's version number was updated to 11.0 in the third beta. The third beta version of macOS Big Sur is 11.0 Beta 3 instead of 10.16 Beta 3. </p> <h4>Server</h4> <p>An early <a href="/facts/Server_computing/dEaYFD7r">server computing</a> 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.<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p> <ul><li><a href="/facts/Mac_OS_X_Server_1.0/06rtm4dw">Mac OS X Server 1.0</a> – code named "Hera", released in 1999</li> <li><a href="/facts/Mac_OS_X_Server/KQxtGUEA">Mac OS X Server</a> – later called "OS X Server" and "macOS Server", released between 2001 and 2022.</li></ul> <h2 id="other-projects">Other projects</h2> <h3>Shipped</h3> <h4>A/ROSE</h4> <p class="note">Main article: <a href="/facts/A/ROSE/L2bbeh5c">A/ROSE</a></p> <p>The <a href="/facts/A/ROSE/L2bbeh5c">Apple Real-time Operating System Environment</a> (A/ROSE) is a small <a href="/facts/Embedded_operating_system/0ue9DzHw">embedded operating system</a> which runs on the Macintosh Coprocessor Platform, an <a href="/facts/Expansion_card/QkWAPnxJ">expansion card</a> for the Macintosh. It is a single "overdesigned" hardware platform on which third-party vendors build practically any product, reducing the otherwise heavy workload of developing a <a href="/facts/NuBus/5UIn0nv8">NuBus</a>-based <a href="/facts/Expansion_card/QkWAPnxJ">expansion card</a>. The first version of the system was ready for use in February 1988.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> </p> <h4>A/UX</h4> <p class="note">Main article: <a href="/facts/A/UX/EzdufrHs">A/UX</a></p> <p>In 1988, Apple released its first <a href="/facts/UNIX/0pNL2seI">UNIX</a>-based OS, <a href="/facts/A/UX/EzdufrHs">A/UX</a>, which is a UNIX operating system with the Mac OS <a href="/facts/Look_and_feel/Uo3RcETT">look and feel</a>. 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 <a href="/facts/Workstation/h5tK4hTt">workstation</a>-class computers. Most of its sales was to the <a href="/facts/Federal_government_of_the_United_States/VJCxUaf7">U.S. government</a>, where MacOS lacks <a href="/facts/POSIX/mQkSt234">POSIX</a> compliance.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> </p> <h4>MAE</h4> <p class="note">Main article: <a href="/facts/Macintosh_Application_Environment/JUnvtS2z">Macintosh Application Environment</a></p> <p>The <a href="/facts/Macintosh_Application_Environment/JUnvtS2z">Macintosh Application Environment</a> (MAE) is a software package introduced by Apple in 1994 that allows certain <a href="/facts/Unix/0pNL2seI">Unix</a>-based computer workstations to run Macintosh applications. MAE uses the <a href="/facts/X_Window_System/ac2vRIQL">X Window System</a> to emulate a <a href="/facts/Macintosh_Finder/LD3gHLDo">Macintosh Finder</a>-style graphical user interface. The last version, MAE 3.0, is compatible with <a href="/facts/System_7.5.3/IwLKo2sX">System 7.5.3</a>. MAE was published for <a href="/facts/Sun_Microsystems/VJ9EzEFd">Sun Microsystems</a> <a href="/facts/SPARCstation/aWMjyvXw">SPARCstation</a> and <a href="/facts/Hewlett-Packard/abuNSYNu">Hewlett-Packard</a> systems. It was discontinued on May 14, 1998.<a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a> </p> <h4>MkLinux</h4> <p class="note">Main article: <a href="/facts/MkLinux/CSW7v9sh">MkLinux</a></p> <p>Announced at the 1996 <a href="/facts/Worldwide_Developers_Conference/hEjVWkoo">Worldwide Developers Conference</a> (WWDC), <a href="/facts/MkLinux/CSW7v9sh">MkLinux</a> is an <a href="/facts/Open-source_software/HzTaB8E9">open source</a> operating system that was started by the <a href="/facts/OSF_Research_Institute/sBn7Q7gt">OSF Research Institute</a> and Apple in February 1996 to port <a href="/facts/Linux/9FvCKSTq">Linux</a> to the <a href="/facts/PowerPC/DqmM9y50">PowerPC</a> 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 its adaptation of the monolithic <a href="/facts/Linux_kernel/dlkduHuA">Linux kernel</a> to run as a server hosted atop the <a href="/facts/Mach_(kernel)/rqK8DES2">Mach microkernel</a> version 3.0.<a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> </p> <h3>Cancelled projects</h3> <h4>Star Trek</h4> <p class="note">Main article: <a href="/facts/Star_Trek_project/yHCEbQJf">Star Trek project</a></p> <p>The <a href="/facts/Star_Trek_project/yHCEbQJf">Star Trek project</a> (as in "to boldly go where no Mac has gone before") was a secret prototype beginning in 1992, to port the classic Mac OS to <a href="/facts/Intel/SMF0gJJX">Intel</a>-compatible <a href="/facts/X86/Kypq5fgu">x86</a> personal computers. In partnership with Apple and with support from Intel, the project was instigated by <a href="/facts/Novell/lABGMT7U">Novell</a>, which was looking to integrate its <a href="/facts/DR-DOS/GcCTKutW">DR-DOS</a> with the Mac OS GUI as a mutual response to the monopoly of <a href="/facts/Microsoft/nGIDDXdx">Microsoft</a>'s <a href="/facts/Windows_3.0/AmCtP94m">Windows 3.0</a> and MS-DOS. A team consisting of four from Apple and four from Novell was got the <a href="/facts/Macintosh_Finder/LD3gHLDo">Macintosh Finder</a> and some basic applications such as <a href="/facts/QuickTime/rA3GQp2j">QuickTime</a>, running smoothly. The project was canceled one year later in early 1993, but was partially reused when porting the Mac OS to <a href="/facts/PowerPC/DqmM9y50">PowerPC</a>.<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a><a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a> </p> <h4>Taligent</h4> <p class="note">Main article: <a href="/facts/Taligent/xLftSbbE">Taligent</a></p> <p><a href="/facts/Taligent/xLftSbbE">Taligent</a> (a <a href="/facts/Portmanteau/d124JEbz">portmanteau</a> of "talent" and "intelligent") is an <a href="/facts/Object-oriented_operating_system/zAwXyN2h">object-oriented operating system</a> and the company producing it. Started as the Pink project within Apple to provide a replacement for the <a href="/facts/Classic_Mac_OS/I5fQq44K">classic Mac OS</a>, it was later spun off into a joint venture with <a href="/facts/IBM/QszA7nwd">IBM</a> as part of the <a href="/facts/AIM_alliance/5KvUj5Q3">AIM alliance</a>, with the purpose of building a competing platform to <a href="/facts/Microsoft_Cairo/Xjjk3NnC">Microsoft Cairo</a> and <a href="/facts/NeXTSTEP/eL0bymga">NeXTSTEP</a>. The development process never worked, and has been cited as an example of a <a href="/facts/Death_march_(project_management)/Af9yVNCa">project death march</a>. Apple pulled out of the project in 1995 before the code had been delivered.<a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a> </p> <h4>Copland</h4> <p class="note">Main article: <a href="/facts/Copland_(operating_system)/vz2aDNhl">Copland (operating system)</a></p> <p><a href="/facts/Copland_(operating_system)/vz2aDNhl">Copland</a> was a project at Apple to create an updated version of the <a href="/facts/Classic_Mac_OS/I5fQq44K">classic Mac OS</a>. It was to have introduced <a href="/facts/Memory_protection/3zDwN2SG">protected memory</a>, <a href="/facts/Preemptive_multitasking/wjgIbWel">preemptive multitasking</a>, and new underlying operating system features, yet still be compatible with existing Mac software. They originally planned the follow-up release Gershwin to add <a href="/facts/Multithreading_(computer_architecture)/ojEKsSNP">multithreading</a> 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 canceled the project outright and sought a suitable third-party replacement. Copland development ended in August 1996, and in December 1996, Apple announced that it was buying <a href="/facts/NeXT/qcCmhJl3">NeXT</a> for its <a href="/facts/NeXTSTEP/eL0bymga">NeXTSTEP</a> operating system.<a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a> </p> <h2 id="timeline">Timeline</h2> <table><tbody><tr><th>Timeline of Mac operating systems <ul><li>v</li><li>t</li><li>e</li></ul></th></tr><tr><td></td></tr></tbody></table> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Comparison_of_operating_systems/HGP8eckk">Comparison of operating systems</a></li> <li><a href="/facts/History_of_the_graphical_user_interface/K2NXGuGh">History of the graphical user interface</a></li> <li><a href="/facts/Mac_(computer)/8GhnXTK0">Mac</a></li> <li><a href="/facts/List_of_Mac_software/PjT8XzRR">List of Mac software</a></li></ul> <h2 id="external-links">External links</h2> <ul><li> Media related to Macintosh operating systems at Wikimedia Commons</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>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. <a href="/wiki/John_Gruber" target="_blank">/wiki/John_Gruber</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Hertzfeld, Andy. "The Original Macintosh: Mea Culpa". folklore.org. Archived from the original on June 19, 2010. Retrieved May 10, 2010. <a href="/wiki/Andy_Hertzfeld" target="_blank">/wiki/Andy_Hertzfeld</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>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. <a href="https://arstechnica.com/apple/reviews/2006/03/osx-fiveyears.ars" target="_blank">https://arstechnica.com/apple/reviews/2006/03/osx-fiveyears.ars</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Gruber, John. "Mountain Lion". Daring Fireball. Archived from the original on August 11, 2015. Retrieved August 15, 2015. <a href="/wiki/John_Gruber" target="_blank">/wiki/John_Gruber</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Honan, Matthew (January 9, 2007). "Apple unveils iPhone". Macworld. Archived from the original on April 15, 2008. Retrieved January 16, 2010. <a href="http://www.macworld.com/article/54769/2007/01/iphone.html" target="_blank">http://www.macworld.com/article/54769/2007/01/iphone.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Linzmayer, Owen W. (2004). Apple Confidential 2.0. No Starch Press. Archived from the original on November 13, 2016. Retrieved October 1, 2016. <a href="https://www.nostarch.com/apple2.htm" target="_blank">https://www.nostarch.com/apple2.htm</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>"The Macintosh Product Introduction Plan". Stanford University Libraries & Academic Information Resources. Stanford University. Archived from the original on July 21, 2010. <a href="https://web.archive.org/web/20100721013724/http://library.stanford.edu/mac/primary/docs/pip83.html" target="_blank">https://web.archive.org/web/20100721013724/http://library.stanford.edu/mac/primary/docs/pip83.html</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Linzmayer, Owen W. (2004). Apple Confidential 2.0. No Starch Press. Archived from the original on November 13, 2016. 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