Mac OS history

Early versions

• System 1.0
• System 2.0
• System 3.0
• System Tools 4.0 (System 3.2, Finder 5.3)
• System Tools 5.0 (System 4.2, Finder 6.0)

System 6

System 6 added MultiFinder, an add-on replacement for the Finder which could run several programs at once. Time was given to the background applications only when the foreground (or "running") applications gave it up (cooperative multitasking[?]), but in fact most of them did via a clever change on the OS's event handling. MultiFinder had been released with earlier systems, but the 6.x systems were the first to make it official and widely used.

The other significant change that System 6.x brought to the Mac was Color QuickDraw, which debuted with the Macintosh II in 1986. This significantly altered the extent and design of the underlying graphics architecture (and its APIs[?]), but it is a credit to Apple that most users were largely unaware of this.

• System 6.0 (Finder 6.1)
• System 6.0.5
• System 6.0.7 (buggy)
• System 6.0.8 (added System 7 file & print sharing compatibility)

System 7

System 7 was a major upgrade to the Mac OS, but the core of the OS remained the same as in prior versions. Instead the new 7.x OS's included a huge number of "high level" additions, considered by some observers to be less well thought out than they might have been.

Although the name was changed to 8.x and 9.x over its history, the OS remained basically the same internally.

• System 7.0 (released in late 1991; integrated MultiFinder into the basic OS)
• System 7.0.1 (introduced with LC II and Quadra series)
• System 7* (System 7 Tuner)
• System 7.1 (the unofficial developer slogan for this release was "System 7.1 Sucks Less")
• System 7.2
• System 7.5
• System 7.5.1
• System 7.5.3
• System 7.5.5
• Mac OS 7.6 (name changed because of the experimental clone[?] program)

• Mac OS 8.0
• Mac OS 8.1
• Mac OS 8.5
• Mac OS 8.6 (now runs on top of a microkernel; can run Carbon API apps)

• Mac OS 9.0
• Mac OS 9.1
• Mac OS 9.2

Mac OS X

Mac OS X is the first real replacement for the older Mac OS's, based on the OpenStep Unix system from NeXT. In addition to the original OpenStep system, OS X adds the Carbon libraries to allow older programming paradigms from the System 7.x core to be run under OS X and gain many of the benefits of this modern OS core. The system also includes Classic, a complete emulator for running older Mac programs.

• Mac OS X 10.0 (switch to BSD-derived Darwin kernel and new Quartz[?]/Aqua[?] GUI; includes 9.1, which it runs in a virtual machine)
• Mac OS X 10.1 (major speedups)
• Mac OS X 10.2 "Jaguar"
• Mac OS X 10.3 "Panther" (to be released in September 2003)

See: Mac OS X history for a more detailed history.