Mac OS history
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Mac OS is the operating system developed by Apple Computer. It has been preinstalled on almost every Macintosh computer sold, and it is also available separately.
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Early versions of Mac OS
Early versions of the operating system were identified by the version numbers of two files they included: System (the kernel) and Finder (the desktop interface).
- System 1.0, Finder 1.0 (January 1984)
- System 1.1, Finder 1.1g (May 1984)
- System 2.0, Finder 4.1 (April 1985)
- System 2.1, Finder 5.0 (September 1985)
- System 3.0, Finder 5.1 (January 1986)
- System 3.2, Finder 5.3 (June 1986)
- System 4.0, Finder 5.4 (January 1987)
- System 4.1, Finder 5.5 (April 1987)
These releases could only run one application at a time, though special application shells such as Switcher (discussed under MultiFinder) could work around this to some extent. Systems 1.0, 1.1, and 2.0 used a flat filing system called MFS (Macintosh File System); its support for folders (subdirectories) was incomplete. System 2.1 (Finder 5.0) introduced the HFS (Hierarchical File System) which had real directories. System 3.0 was introduced with the Mac Plus, adding support for several new technologies including SCSI and AppleTalk. System 4.0 came with the Mac SE and Macintosh II.
Changes in early Macintosh operating systems are best reflected in the version number of the Finder, where major leaps are found between 1.x, 4.x, 5.x, and 6.x.
System 5
System 5 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. The other significant change that System 5 brought to the Mac was Color QuickDraw, which debuted with the Macintosh II. 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, and perhaps more importantly existing code, were largely unaware of this.
System 5 was also the first Macintosh operating system to be given a unified "Macintosh System Software" version number, as opposed to the numbers used for the System and Finder files.
- System Software 5.0 [System 4.2, Finder 6.0, MultiFinder 1.0]
- System Software 5.1 [System 4.3, Finder 6.0, MultiFinder 1.0]
System 6
System 6 consolidated the previous releases into a much more complete and stable operating system. It also moved the Mac to true 32-bit memory addressing - necessary with the ever increasing amounts of RAM available. Earlier systems used the lower 24 bits for addressing, and the upper 8 bits for flags. This was a neat solution on the earlier Macs with their very limited amounts of RAM, but became a liability later. Code that assumed the 24 + 8 bit addressing was "not 32-bit clean" in Apple's words, and developers were required to excise such assumptions from their code.
- System Software 6.0 [System 4.4, Finder 6.1, MultiFinder 1.1] (the version numbers of the System and MultiFinder files were changed to 6.0 just before the public release)
- System Software 6.0.1
- System Software 6.0.2
- System Software 6.0.3
- System Software 6.0.4
- System Software 6.0.5
- System Software 6.0.7
- System Software 6.0.8 (identical to System 6.0.7, but configured with System 7.0 printing software to ease sharing printers with System 7 machines)
System 7
System 7.0 was a major upgrade to the Mac OS. Systems 7.1 and 7.5 introduced a large number of "high level" additions, considered by some observers to be less well thought out than they might have been.
Although the version number was subsequently changed to 8.x and 9.x, the internal core of the OS remained basically the same.
- 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 Tuner (update for both 7.0 and 7.0.1)
- System 7.1
- System 7.1 Pro (version 7.1.1, combined with PowerTalk, Speech Manager & Macintalk, Thread Manager)
- System 7.1.2 (first version for Macs equipped with a PowerPC processor)
- System 7.5
- System 7.5.1 (System 7.5 Update 1.0) -- the first Macintosh operating system to call itself "Mac OS"
- System 7.5.2 -- first version for PowerMacs that use PCI expansion cards, usable only on these Power Macs and PowerBooks 5300 and Duo 2300
- System 7.5.3 (System 7.5 Update 2.0)
- System 7.5.3L -- only for Mac clones
- System 7.5.3 Revision 2
- System 7.5.3 Revision 2.1 -- only for Performa 6400/180 and 6400/120
- System 7.5.5
- Mac OS 7.6 (name formally changed because of the experimental clone program, although System 7.5.1 and later used the "Mac OS" name on the splash screen)
- Mac OS 7.6.1
Macintosh Performa computers used to have their own, exclusive operating system before they were merged into System 7.5.
- System 7.0P1
- System 7.1P1
- System 7.1P2
- System 7.1P3 -- last release with new features
- System 7.1P4
- System 7.1P5
- System 7.1P6
Mac OS 8
Mac OS 8 was very much a stop-gap version which was brought out to try and keep the Mac OS moving forward during a very trying time for the platform. 8.0 added a number of features from the stillborn Copland project, while leaving the underlying operating system unchanged. The GUI was changed in appearance to a new shaded greyscale look called Platinum, and the ability to change the appearance themes (a.k.a skins) was added with a new control panel. This capability was provided by a new "appearance" API layer within the OS, one of the few significant changes. Mac OS 8.1 also saw the introduction of an updated version of HFS, HFS+, which fixed many of the limitations of the earlier system - in fact it is still in use today on Mac OS X. There were some other interface changes such as separating network features from printing (the venerable, and rather odd Chooser was at last headed for retirement), and some improvements to application switching. However, in most significant respects, Mac OS 8 was not very different from System 7.
- Mac OS 8.1 (last version to run on Macs with either a m68k or PowerPC processor, earliest version that can run Carbon API apps)
- Mac OS 8.5 (first version to run solely on Macs equipped with a PowerPC processor)
- Mac OS 8.6 (now runs on top of a nanokernel)
Mac OS 9
Mac OS 9 was a steady evolution from Mac OS 8. In fact the only reason that the version got increased from 8 to 9 was to pave the way to the future OS X ("ten"), rather than leave a gap in the version numbers which might have discouraged some to make the eventual change to OS X. Rumour has it that OS 9 was originally to be named Mac OS 8.7. OS 9 also added some transitional technologies to help application developers adopt some OS X features sooner rather than later, again easing the transition. These included new APIs for the file system, and the bundling of the Carbon library that apps could link against instead of the traditional API libraries - apps that were adapted to do this can be run natively on OS X as well. Other changes were made in OS 9 to allow it to be booted in the "classic environment" within OS X. This is a compatibility layer in OS X (in fact an OS X application, known in developer circles as "the blue box") that runs a complete Mac OS 9 operating system, so allowing applications that have not been ported to Carbon to run on Mac OS X. This is reasonably seamless, though "classic" applications retain their original OS 8/9 appearance and do not gain the OS X "Aqua" appearance.
- Mac OS 9.0
- Mac OS 9.0.2
- Mac OS 9.0.3
- Mac OS 9.0.4
- Mac OS 9.1
- Mac OS 9.2
- Mac OS 9.2.1
- Mac OS 9.2.2
Mac OS X
See Mac OS X history.
External links
- Mac OS Timeline (http://www.theapplemuseum.com/index.php?id=tam&page=timeline&subpage=os/)
- Apple Macintosh before System 7 (http://homepage.mac.com/chinesemac/earlymacs/)
- A History of Apple's Operating Systems (http://www.kernelthread.com/mac/oshistory/)