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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Operating systems (OS)

An operating system (OS) is system software that manages computer hardwaresoftware resources, and provides common services for computer programs.

Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor timemass storage, printing, and other resources.

For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware,[1][2] although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers.

The dominant general-purpose[3] desktop operating system is Microsoft Windows with a market share of around 76.45%. macOS by Apple Inc. is in second place (17.72%), and the varieties of Linux are collectively in third place (1.73%).[4] In the mobile sector (including smartphones and tablets), Android’s share is up to 72% in the year 2020.[5] According to third quarter 2016 data, Android’s share on smartphones is dominant with 87.5 percent with also a growth rate of 10.3 percent per year, followed by Apple’s iOS with 12.1 percent with per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent.[6] Linux distributions are dominant in the server and supercomputing sectors. Other specialized classes of operating systems (special-purpose operating systems)[7][8]), such as embedded and real-time systems, exist for many applications. Security-focused operating systems also exist. Some operating systems have low system requirements (i.e. light-weight Linux distribution). Others may have higher system requirements.

Some operating systems require installation or may come pre-installed with purchased computers (OEM-installation), whereas others may run directly from media (i.e. live cd) or flash memory (i.e. usb stick).

Apple macOS History

Apple iTunes – 2001 AD

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Steve Jobs (1955–2011), Jeff Robbin (dates unavailable), Bill Kincaid (b. 1956), Dave Heller (dates unavailable)

“The music business at the end of the 20th century was in an epic fight to maintain its profitable business model. Music had become 1s and 0s and was being widely shared, without compensation, among users through online services such as Napster. The industry was filing suit against both the services and their users to protect copyrights.

Apple cofounder Steve Jobs saw an opportunity and in 2000 purchased SoundJam MP, a program that functioned as a music content manager and player. It was developed by two former Apple software engineers, Bill Kincaid and Jeff Robbin, along with Dave Heller, who all took up residence at Apple and evolved the product into what would become iTunes.

iTunes debuted on January 9, 2001, at Macworld Expo in San Francisco. For the first two years, iTunes was promoted as a software jukebox that offered a simple interface to organize MP3s and convert CDs into compressed audio formats. In October 2001, Apple released a digital audio player, the iPod, which would neatly sync with a user’s iTunes library over a wire. This hardware release set the stage for the next big evolution, which came with iTunes version 4 in 2003—the iTunes Music Store, which launched with 200,000 songs. Now users could buy licensed, high-quality digital music from Apple.

Buying music from a computer company was a radical concept. It flipped the traditional business model and gave the music industry an organized, legitimate mechanism in the digital space to profit from, and protect, their intellectual property.

The music labels agreed to participate in the iTunes model and allowed Jobs to sell their inventory in part because he agreed to copy-protect their songs with Digital Rights Management (DRM). (Apple significantly eased the DRM-based restrictions for music in 2009.) Consumers embraced iTunes in part because they could buy single songs again—no longer did they have to purchase an entire album to get one or two tracks.

In the following years, iTunes would snowball into a media juggernaut adding music videos, movies, television shows, audio books, podcasts, radio, and music streaming—all of which were integrated with new products and services from Apple, including Apple TV, the iPhone, and the iPad.”

SEE ALSO MPEG (1988), Diamond Rio MP3 Player (1998)

Apple’s Steve Jobs announces the release of new upgrades to iTunes and other Apple products at a press conference in San Francisco, California, on September 1, 2010.

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