MAC:HISTORY

Mac OS X is based on the Mach kernel and is derived from the Berkeley Software Distribution (BSD) and later, certain parts from FreeBSD's and NetBSD's implementation of Unix in Nextstep. Nextstep was the object-oriented operating system developed by Steve Jobs' company NeXT after he left Apple in 1985.[7] While Jobs was away from Apple, Apple tried to create a "next-generation" OS through the Taligent, Copland and Gershwin projects, with little success.

Eventually, NeXT's OS—then called OPENSTEP—was selected to be the basis for Apple's next OS, and Apple purchased NeXT outright.[8] Steve Jobs returned to Apple as interim CEO, and later became CEO again, shepherding the transformation of the programmer-friendly OPENSTEP into a system that would be adopted by Apple's primary market of home users and creative professionals. The project was first known as Rhapsody and was later renamed to Mac OS X.[9]

With each new version, Mac OS X evolved away from a focus on backward compatibility with the earlier versions of Mac OS, toward an emphasis on "digital lifestyle" applications such as the iLife suite, enhanced business applications (iWork), and integrated home entertainment (the Front Row media center). Each version also included modifications to the general interface, such as the brushed metal appearance added in version 10.2, the non-pinstriped titlebar appearance in version 10.4, and in 10.5 the removal of the previous brushed metal styles in favor of the "Unified" gradient window style.