Apple macOS Operating Systems Software Engineering

macOS – OSX – OS X

This article is about the current Apple operating system for Mac computers. For pre-2001 versions, see Classic Mac OS.

MacOS wordmark (2017).svg
DeveloperApple Inc.
Written inCC++[1]Objective-CSwift[2]assembly language
OS familyUnixMacintosh
Working stateCurrent
Source modelClosed source (with open source components)
Initial releaseMarch 24, 2001; 19 years ago
Latest release11.2.3[3] (20D91)[4] (March 8, 2021; 1 day ago) [±]
Latest preview11.3 beta 3[5] (20E5196f)[6] (March 2, 2021; 7 days ago) [±]
Marketing targetPersonal computing
Available in39 languages[7]
List of languages[as of macOS Catalina]: Arabic, Catalan, Croatian, Chinese (Hong Kong), Chinese (Simplified), Chinese (Traditional), Czech, Danish, Dutch, English (Australia), English (United Kingdom), English (United States), Finnish, French (Canada), French (France), German, Greek, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Malay, Norwegian, Polish, Portuguese (Brazil), Portuguese (Portugal), Romanian, Russian, Slovak, Spanish (Latin America), Spanish (Spain), Swedish, Thai, Turkish, Ukrainian, Vietnamese
Update methodSystem Preferences (10.14–)Mac App Store (10.810.13.6)Software Update (
PlatformsARM64 (11.0–)x86-64 (10.4.7–)IA-32 (10.4.410.6.8)PowerPC (
Kernel typeHybrid (XNU)
Default user interfaceAqua (Graphical)
LicenseCommercial softwareproprietary software
Preceded byClassic Mac OSNeXTSTEP
Support status

macOS (/ˌmækoʊˈɛs/;[8] previously Mac OS X and later OS X) is a series of proprietary graphical operating systems developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple’s Mac computers. Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS, after Microsoft Windows.[9][10]” (WP)

“macOS is the direct successor to the classic Mac OS, the line of Macintosh operating systems with nine releases from 1984 to 1999. macOS adopted the Unix kernel and inherited technologies developed between 1985 and 1997 at NeXT, the company that Apple co-founder Steve Jobs created after leaving Apple in 1985. Releases from Mac OS X 10.5 Leopard[11] and thereafter are UNIX 03 certified.[12] Apple’s mobile operating system, iOS, has been considered a variant of macOS.[13]” (WP)

“The first desktop version, Mac OS X 10.0, was released in March 2001, with its first update, 10.1, arriving later that year. The “X” in Mac OS X and OS X is the Roman numeral for the number 10 and is pronounced as such. The X was a prominent part of the operating system’s brand identity and marketing in its early years, but gradually receded in prominence since the release of Snow Leopard in 2009. Apple began naming its releases after big cats, which lasted until OS X 10.8 Mountain Lion. Since OS X 10.9 Mavericks, releases have been named after locations in California.[14] Apple shortened the name to “OS X” in 2012 and then changed it to “macOS” in 2016, adopting the nomenclature that they were using for their other operating systems, iOSwatchOS, and tvOS. With Big Sur, Apple advanced the macOS major version number for the first time, changing it to 11 for Big Sur from the 10 used for all previous releases.” (WP)

“macOS has supported three major processor architectures. It first supported PowerPC-based Macs in 1999. Starting in 2006, with the Mac transition to Intel processors, it ran on Macs using Intel x86 processors. Most recently, starting in 2020, with the Mac transition to Apple Silicon, it runs on Macs using 64-bit ARM-based Apple Silicon processors.” (WP)


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History Software Engineering

Apple Swift Programming Language Invented – 2014 AD

Return to Timeline of the History of Computers

Created by Apple and released on June 2, 2014, the Swift programming language helps create programs and apps for iOSmacOS, the Apple Watch, and AppleTV.

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History Software Engineering Swift

Objective-C Programming Language Invented by Brad Cox and Tom Love – 1988 AD

Return to Timeline of the History of Computers

Developed in the mid-1980s by Brad Cox and Tom Love, the Objective-C programming language was officially licensed by NeXT in 1988.

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