"MACOS" redirects here. For the American humanities teaching program, see Man: A Course of Study.
Mac OS |
The upcoming release of Mac OS, 10.7 Lion. |
Company / developer | Apple |
OS family | Mac OS (System 1-7, Mac OS 8-9), Unix (Mac OS X) |
Working state | Publicly released |
Source model | Closed source (with open source components) |
Latest stablerelease | 10.6.6  (January 6, 2011; 51 days ago (2011-01-06)) [+/−] |
License | Proprietary EULA |
Official website | www.apple.com/macosx/ |
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. (formerly Apple Computer, Inc.) for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical userinterface. The original form of what Apple would later name the "Mac OS" was the integral and unnamed system software first introduced in 1984 with the original Macintosh, usually referred to simply as the System software.
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 todistance it from other operating systems such as MS-DOS, which was more arcane and technically challenging. Much of this early system software was held in ROM, with updates typically provided free of charge by Apple dealers on floppy disk. As increasing disk storage capacity and performance gradually eliminated the need for storing much of the advanced GUI operating system in the ROM, Appleexplored clones while positioning major operating system upgrades as separate revenue-generating products, first with System 7.1 and System 7.5, then with Mac OS 7.6 in 1997.
Early versions of the Mac OS were compatible only with Motorola 68000-based Macintoshes. As Apple introduced computers with PowerPC hardware, the OS was ported to support this architecture as well. Mac OS 8.1 was the last versionthat could run on a 68000-class processor (the 68040). Mac OS X, which has superseded the "Classic" Mac OS, is compatible with both PowerPC and Intel processors through to version 10.5 ("Leopard"). Version 10.6 ("Snow Leopard") supports only Intel processors.
The early Macintosh operating system initially consisted of two pieces of software, called "System" and"Finder", each with its own version number. System 7.5.2 was the first to include the Mac OS logo (a variation on the original Happy Mac startup icon), and Mac OS 7.6 was the first to be named "Mac OS".
Before the introduction of the later PowerPC G3-based systems, significant parts of the system were stored in physical ROM on the motherboard. The initial purpose of this was to avoid using up thelimited storage of floppy disks on system support, given that the early Macs had no hard disk. (Only one model of Mac was ever actually bootable using the ROM alone, the 1991 Mac Classic model.) This architecture also allowed for a completely graphical OS interface at the lowest level without the need for a text-only console or command-line mode. Boot time errors, such as finding no functioningdisk drives, were communicated to the user graphically, usually with an icon or the distinctive Chicago bitmap font and a Chime of Death or a series of beeps. This was in contrast to PCs of the time, which displayed such messages in a mono-spaced font on a black background, and required the use of the keyboard, not a mouse, for input. To provide such niceties at a low level, Mac OS depended on coresystem software in ROM on the motherboard, a fact that later helped to ensure that only Apple computers or licensed clones (with the copyright-protected ROMs from Apple) could run Mac OS.
Mac OS can be divided into two families:
* The Mac OS Classic family, which was based on Apple's own code
* The Mac OS X operating system, developed from Mac OS Classic family, and NeXTSTEP, which was...