OS X (mac OS) is Apple Inc.'s current Mac OS line of operating systems.
To ease the transition, versions of OS X until 10.5 were able to run Mac OS 9 and its applications in a virtual environment.Unlike Mac OS 9 and earlier, OS X is a UNIX operating system built on technology that had been developed at Ne XT through the second half of the 1980s and up until Apple purchased the company in early 1997.It was first released in 1999 as Mac OS X Server 1.0, with a desktop-oriented version (Mac OS X v10.0) following in March 2001.Since then, six more distinct "client" and "server" editions of Mac OS X were released.Starting with Mac OS X v10.7 Lion, OS X Server is no longer offered as a separate operating system product; instead, the server management tools are available for purchase separately.
Beginning with the Intel build of Mac OS X v10.5 Leopard, most releases have been certified as UNIX systems conforming to the Single UNIX Specification.
and from his own pockets — to create the "next big thing". Ne XT hardware was advanced for its time, being the first workstation to include a DSP and a high-capacity optical disc drive, but it had several quirks and design problems and was expensive compared to the rapidly commoditizing workstation market.
The hardware was phased out in 1993; however, the company's object-oriented operating system Ne XTSTEP had a more lasting legacy.
Ne XTSTEP was based on the Mach kernel developed at CMU (Carnegie Mellon University) and BSD, an implementation of Unix dating back to the 1970s.
It featured an object-oriented programming framework based on the Objective-C language.
This environment is known today in the Mac world as Cocoa.