Architecture of macOS

<h2 id="development">Development</h2>
<p class="note">Main article: <a href="/facts/History_of_macOS/qR6fo5mj">History of macOS</a></p>
<h3>NeXTSTEP</h3>
<p class="note">Main article: <a href="/facts/NeXTSTEP/eL0bymga">NeXTSTEP</a></p>
<p>NeXTSTEP used a hybrid kernel that combined the <a href="/facts/Mach_kernel/rqK8DES2">Mach 2.5</a> kernel developed at <a href="/facts/Carnegie_Mellon_University/XKd7L2KA">Carnegie Mellon University</a> with subsystems from <a href="/facts/BSD/XQKcURrh">4.3BSD</a>. NeXTSTEP also introduced a new windowing system based on <a href="/facts/Display_PostScript/Kt6Pj1D0">Display PostScript</a> that intended to achieve better <a href="/facts/WYSIWYG/aGmcHWpX">WYSIWYG</a> systems by using the same language to draw content on monitors that drew content on printers. NeXT also included <a href="/facts/Object-oriented_programming/TxNMEcao">object-oriented programming</a> tools based on the <a href="/facts/Objective-C/5mM557BW">Objective-C</a> language that they had acquired from <a href="/facts/Stepstone/kfsgUuwY">Stepstone</a> and a collection of Frameworks (or Kits) that were intended to speed software development. NeXTSTEP originally ran on <a href="/facts/Motorola/ztqczx68">Motorola</a>'s <a href="/facts/68k/jxd7VPlW">68k</a> processors, but was later ported to <a href="/facts/Intel/SMF0gJJX">Intel</a>'s <a href="/facts/X86/Kypq5fgu">x86</a>, <a href="/facts/Hewlett-Packard/abuNSYNu">Hewlett-Packard</a>'s <a href="/facts/PA-RISC/gjDs1HEh">PA-RISC</a> and <a href="/facts/Sun_Microsystems/VJ9EzEFd">Sun Microsystems</a>' <a href="/facts/SPARC/m7KhEtET">SPARC</a> processors. Later on, the developer tools and frameworks were released, as <a href="/facts/OpenStep/RTKQxPR1">OpenStep</a>, as a development platform that would run on other operating systems.
</p>
<h3>Rhapsody</h3>
<p class="note">Main article: <a href="/facts/Rhapsody_(operating_system)/KYa1NJIl">Rhapsody (operating system)</a></p>
<p>On February 4, 1997, Apple acquired NeXT and began development of the <a href="/facts/Rhapsody_(operating_system)/KYa1NJIl">Rhapsody</a> operating system. Rhapsody built on NeXTSTEP, <a href="/facts/Porting/7s6tFs8B">porting</a> the core system to the <a href="/facts/PowerPC/DqmM9y50">PowerPC</a> architecture and adding a redesigned user interface based on the <a href="/facts/Platinum_(theme)/w1oeBWSJ">Platinum</a> user interface from <a href="/facts/Mac_OS_8/Vde5S5hl">Mac OS 8</a>. An emulation layer called <a href="/facts/Classic_(Mac_OS_X)/7uDAhFUz">Blue Box</a> allowed Mac OS applications to run within an actual instance of the Mac OS and an integrated <a href="/facts/Java_platform/fpn6x8WL">Java platform</a>.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> The Objective-C developer tools and Frameworks were referred to as the <a href="/facts/Cocoa_(API)/p10p5aFI">Yellow Box</a> and also made available separately for <a href="/facts/Microsoft_Windows/bwhAhuSL">Microsoft Windows</a>. The Rhapsody project eventually bore the fruit of all Apple's efforts to develop a new generation Mac OS, which finally shipped in the form of <a href="/facts/Mac_OS_X_Server/KQxtGUEA">Mac OS X Server</a>.
</p>
<h3>Mac OS X</h3>

<p>At the 1998 <a href="/facts/Worldwide_Developers_Conference/hEjVWkoo">Worldwide Developers Conference</a> (WWDC), Apple announced a move that was intended as a response to complaints from Macintosh software developers who were not happy with the two options (Yellow Box and Blue Box) available in Rhapsody. Mac OS X would add another developer <a href="/facts/API/GMlN4vUr">API</a> to the existing ones in Rhapsody. Key APIs from the <a href="/facts/Macintosh_Toolbox/Pgvfu771">Macintosh Toolbox</a> would be implemented in Mac OS X to run directly on the BSD layers of the operating system instead of in the emulated Macintosh layer. This modified interface, called <a href="/facts/Carbon_(API)/KAIwFWI2">Carbon</a>, would eliminate approximately 2000 troublesome API calls (of about 8000 total) and replace them with calls compatible with a modern OS.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
</p><p>At the same conference, Apple announced that the Mach side of the kernel had been updated with sources from the <a href="/facts/OSFMK/mck5Bgyq">OSFMK</a> 7.3 (Open Source Foundation's MK operating system)<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> and the BSD side of the kernel had been updated with sources from the <a href="/facts/FreeBSD/RKsFTm7F">FreeBSD</a>, <a href="/facts/NetBSD/PTm5HWls">NetBSD</a> and <a href="/facts/OpenBSD/xmPS9tek">OpenBSD</a> projects.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> They also announced a new driver model called I/O Kit, intended to replace the Driver Kit used in NeXTSTEP citing Driver Kit's lack of power management and hot-swap capabilities and its lack of automatic configuration capability.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p><p>At the 1999 WWDC, Apple revealed <a href="/facts/Quartz_(graphics_layer)/FLvFwpYt">Quartz</a>, a new <a href="/facts/Portable_Document_Format/C9Mn1vYL">Portable Document Format</a> (PDF) based windowing system for the operating system that was not encumbered with licensing fees to <a href="/facts/Adobe_Systems/Bj1d5XvJ">Adobe</a> like the Display PostScript windowing system of NeXTSTEP. Apple also announced that the Yellow Box layer had been renamed <a href="/facts/Cocoa_(API)/p10p5aFI">Cocoa</a> and began to move away from their commitment to providing the Yellow Box on Windows. At this WWDC, Apple also showed Mac OS X booting off of a <a href="/facts/HFS_Plus/sWk14kM5">HFS Plus</a> formatted drive for the first time.
</p><p>The first public release of Mac OS X released to consumers was a <a href="/facts/Mac_OS_X_Public_Beta/YhCaCyIj">Public Beta</a> released on September 13, 2000.
</p>

<h3>Bibliography</h3>
<ul><li>Levin, Jonathan (September 25, 2019). <i>*OS Internals, Volume I: User Mode</i> (v1.3.3.7 ed.). Technologeeks. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-9910555-6-2.</li>
<li>Levin, Jonathan (October 16, 2019b). <i>*OS Internals, Volume II: Kernel Mode</i> (v1.0 ed.). Technologeeks. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-9910555-7-9.</li>
<li>Singh, Amit (June 19, 2006). <i>Mac OS X Internals: A Systems Approach</i>. Addison-Wesley Professional. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0-13-270226-3.</li></ul>
<h2 id="external-links">External links</h2>
<ul><li><a href="https://www.apple.com/macos/">Official Website</a></li>
<li><a href="https://gadgetraja.com/macos-mojave-a-much-better-functional-experience/">MacOS Mojave</a></li>
<li><a href="https://arstechnica.com/apple/2014/10/os-x-10-10/">Mac OS X Reviews</a></li>
<li><a href="http://www.osxbook.com/">Mac OS X Internals</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Apple PR (1997-11-19). "Apple Extends Rhapsody Developer Release with Mac OS Compatibility Environment, Code-Named "Blue Box"". apple.com. Archived from the original on 1998-12-02. Retrieved 2006-10-13. <a href="https://web.archive.org/web/19981202202310/http://product.info.apple.com/pr/press.releases/1998/q1/971119.pr.rel.macos.html" target="_blank">https://web.archive.org/web/19981202202310/http://product.info.apple.com/pr/press.releases/1998/q1/971119.pr.rel.macos.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Scott Anguish (May 1998). "WWDC 98 Summary". stepwise.com. Retrieved 2006-10-13. [permanent dead link‍] <a href="http://www.stepwise.com/SpecialCoverage/WWDC98/Summary.html" target="_blank">http://www.stepwise.com/SpecialCoverage/WWDC98/Summary.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Magee, Jim. WWDC 2000 Session 106 – Mac OS X: Kernel.  14 minutes in. Archived from the original on 2021-12-21. <a href="https://www.youtube.com/watch?v=ggnFoDqzGMU" target="_blank">https://www.youtube.com/watch?v=ggnFoDqzGMU</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Scott Anguish (May 1998). "WWDC 98 Summary". stepwise.com. Retrieved 2006-10-13. [permanent dead link‍] <a href="http://www.stepwise.com/SpecialCoverage/WWDC98/Summary.html" target="_blank">http://www.stepwise.com/SpecialCoverage/WWDC98/Summary.html</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Scott Anguish (1998-05-14). "Rhapsody Core OS: Intro to the I/O Driver Architecture". stepwise.com. Retrieved 2006-10-13. [permanent dead link‍] <a href="http://www.stepwise.com/SpecialCoverage/WWDC98/Thursday-IOKit.html" target="_blank">http://www.stepwise.com/SpecialCoverage/WWDC98/Thursday-IOKit.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
</ol>

Architecture of macOS open-in-new

Architecture of macOS