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Mac OS X

Mac OS X, the latest version of Mac OS, is an operating system for Macintosh computers from Apple that combines popular features of the traditional Macintosh user interface on top of a stable Unix operating environment. The pronunciation OS 'ten' is favored by Apple, to stress continuity with previous Macintosh operating systems. Others say OS 'ex' , both to emphasize the relationship with Unix, and because of the presence of the roman numeral X in the name of the operating system.

OS X was created by combining Darwin, an open source Unix-like environment, which is based on the BSD source tree and the Mach microkernel, with a GUI, called Aqua, developed by Apple Computer. The operating system saw its first commercial release in 2001.

Table of contents
1 History
2 Description
3 Notable interface features
4 Versions
5 Software
6 Press release
7 External links


See Mac OS X history.

What is today Mac OS X originally started in 1989 as NeXTSTEP, the object-oriented operating system developed by Steve Jobs' NeXT company after he was forced from Apple in 1986. After disappointing sales of the computers designed to run it, NeXTSTEP was ported to a number of other platforms in the early 1990s, but never became very popular because of the arguably high pricing that NeXT applied to its products, especially for its development tools. NeXT had justified this, saying that high prices accompany high quality, though many were not willing to take the NeXT route, beneficial or not. NeXTSTEP then underwent an evolution into OPENSTEP, which separated the object layers from the operating system below, allowing it to run with less modification on other platforms. However, by this point in time, a number of other companies, notably Apple, IBM, and Microsoft, were claiming they would soon be releasing similar object-oriented operating systems and development tools of their own—however some of these efforts, such as Taligent, did not fully come to fruition.

Coincident with these developments, by the mid-1990s Apple's own operating system had reached the limits of its single-user, co-operative multitasking architecture. A massive development effort to replace it, known as Copland, was started in 1994, but was generally realized outside of Apple to be a hopeless case due to political infighting. By 1996 Copland was nowhere near ready for release, and the effort was eventually cancelled outright. Some elements of Copland were incorporated in Mac OS 8, released in 1997.

At this point the new CEO of Apple turned to the market to look for a replacement - a modern operating system with the UI Apple users expected, and the performance and modern features needed to move the platform forward. After some time, and a publicly rancorous debate, OPENSTEP was selected as the basis and Apple purchased NeXT outright.

At first the plan was to develop a new operating system based almost entirely on OPENSTEP, with an emulator for running "classic" Macintosh applications. The result was known under the code name Rhapsody, slated for release in 1998. It was expected that developers would port their software to the considerably more powerful OPENSTEP libraries once they learned of its power and flexibility, instead, perhaps unexpectedly, the vast majority of developers told Apple that this would never occur, and that they would rather leave the platform entirely. Interestingly enough, the newer Cocoa libraries developed by Apple are almost entirely identical to the original OPENSTEP libraries, and are recently coming into greater use.

Another re-design was then started, this time promoting the original Macintosh APIs, re-written as Unix libraries, as first-class citizens of the new operating system. Another change was required by the switch from OPENSTEP's Display PostScript engine to one that was license free, known as Quartz. The resulting changes delayed the introduction of the operating system by about two years.

During this time the lower layers of the operating system, consisting of the Mach kernel and the BSD layers on top, was re-packaged and released under an open source license as Darwin. The Darwin kernel provides an extremely stable and flexible operating system which rivals many other Unix implementations, however it is unclear if it sees any real use outside the Macintosh community.


Mac OS X 10.2 Jaguar screenshot thumbnail

Many of OS X's users consider its Aqua GUI to be the most attractive and functional in existence, which has been imitated by others; there are Aqua lookalikes for other operating systems, (e.g., mosfet liquid). Interface skins imitating the Aqua look exist for many Microsoft Windows programs, such as Winamp.

This combination of GUI and kernel has very recently become the most popular-selling Unix environment to date by sheer numbers. (Note that Mac OS X is not officially a Unix OS, as Apple has not sought The Open Group branding, as the cost of certification would make the OS prohibitively expensive.)

OS X is compatible with older Mac OS applications by using Classic, an application which allows users to run Mac OS 9.x within OS X, so that most older applications, such as the ubiquitous SimpleText, etc., run as they would under Mac OS 9.x. In addition, the Carbon APIs were added to permit legacy code to be quickly ported to run natively on both OS X and Mac OS 9.x. A fourth option for developers is to write applications in the Java platform, which OS X supports.

OS X can run many BSD or Linux software packages once compiled for the platform. Compiled binaries are normally distributed as OS X Packages; but may still require command-line configuration or compilation. Projects like Fink and DarwinPorts provide precompiled or preformatted packages for many standard packages. Apple's X11 will make it even easier to exchange packages with UNIX and Linux users.

Notable interface features

In 2001, Apple released Mac OS X version 10.0 on March 24, which brought OS X to the public awareness. It was praised for its completeness and stability at such an early point in its development (it being a total departure from previous Apple releases). Despite this, it was criticized for being slow, leading many (including Steve Jobs) to consider it an excellent beta release. In September of that year, version 10.1 was released as a free update, increasing the speed and performance of the system as well as providing missing features, such as DVD playback.

In 2002, Apple followed up with Jaguar, Mac OS X 10.2, which brought profound performance enhancements, a newer, sleeker look, and many powerful enhancements (over 150, according to Apple). Mac OS X is now the only system shipping on new Macintosh computers.

Mac OS X 10.3, Panther, was released on October 24, 2003, and in addition to providing much improved performance also incorporated the most extensive update to the user interface, Aqua. The update included as many or more new features as Jaguar did.



This list includes software created for Mac OS X by Apple. All of these applications ship with the operating system.

Press release

Here, courtesy
Apple Computer's press relations, is information on OS X (wikified):

...combines the power and stability of UNIX with the simplicity and elegance of the Macintosh.

...innovative time-saving features including a new Finder and the Dock designed to help you navigate and organize your system, and give you instant access to your most frequently used applications, folders....

...built on three cutting-edge graphics technologies Quartz, OpenGL, and QuickTime...

...the foundation of Mac OS X [is] an industrial-strength, UNIX-based core operating system—called Darwin—that delivers unprecedented stability and performance...powerful, advanced features such as protected memory, preemptive multitasking, advanced memory management, and symmetric multiprocessing...

...Seamless device connectivity and industry-leading applications...

...includes powerful, easy-to-use tools for making your own movies, managing your music, and capturing photos from your digital camera. Built-in support for burning music and data CDss, playing DVD movies, and even authoring your own DVDs...

...lets you run thousands of existing Mac OS 9-compatible applications, while... Mac OS X provide[s] a foundation for great new applications.

External links