There is a long and involved history on this OS that can be traced back at least 15 years. Mac OS X began as an implementation of the OpenStep API, OPENSTEP, which was developed from the NeXTSTEP operating system. Apple then added its Cocoa extensions. Another example of an OpenStep-compatible system is GNUstep.
The pronunciation OS 'ten' is favored by Apple, to stress continuity with previous Macintosh operating systems. Others say OS 'ex' to emphasise the relationship with Unix, but probably mostly because the name of the operating system has the letter X in it.
OS X was created by combining Darwin, an open source UNIX kernel based environment, which is based on the BSD source tree and the Mach microkernel, with a GUI, called Aqua, made by Apple Computer. It was first released in 2001.
The Darwin kernel provides an extremely stable and flexible operating system which rivals many other Unix implementations.
Many of OS X's users consider its Aqua GUI to be the most beautiful and functional in existence, which has been imitated by others, There are Aqua lookalikes for other operating systems, (eg mosfet liquid). Interface skins[?] imitating the Aqua look exist for many Windows programs, such as Winamp.
It is a powerful combination, and has very recently become the most popular-selling Unix environment to date by sheer numbers. (Although it 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.
OS X can run many BSD or Linux software packages, once they've been 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 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.
In 2001, Apple released Mac OS X version 10.1, 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 criticised for being slow, leading many (including Steve Jobs) to consider it an excellent beta release.
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.
In 2003, Steve Jobs confirmed at Apple's Worldwide Developers Conference (WWDC) that devlopment of Jaguar was over and being replaced by Panther, the 10.3 verison of Mac OS X which was previewed at WWDC. Panther will be released by the end of the year 2003.
...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....
...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 CDs, 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.