Mac OS

Mac OS, which stands for Macintosh Operating System, is the trademarked name for a series of graphical user interface-based operating systems developed by Apple Computer for their Macintosh line of computer systems. The Mac OS is often credited with popularizing the graphical user interface. It was first introduced in 1984 with the original Macintosh 128K.

Apple deliberately downplayed the existence of the operating system in the early years of the Macintosh to help make the machine appear more user-friendly and to distance it from other operating systems such as MS-DOS, which were portrayed as arcane and technically challenging. Apple wanted Macintosh to be portrayed as a computer "for the rest of us". The term "Mac OS" did not really exist until it was officially used during the mid-1990s. The term has since been applied to all versions of the Mac system software as a handy way to refer to it when discussing it in context with other operating systems.

Earlier versions of the Mac OS were compatible only with Motorola 68000-based Macintoshes, while later versions were also compatible with the PowerPC (PPC) architecture. Most recently, Mac OS X has become compatible with Intel's x86 architecture.