. Classic Mac OS is a colloquial term used to describe a series of developed for the family of by from 1984 until 2001, starting with and ending with. The Macintosh operating system is credited with having popularized the concept. It was included with every Macintosh that was sold during the era it was developed, and many updates to the system software were done in conjunction with the introduction of new Macintosh systems.

Apple released the on January 24, 1984. The, which had no official name, was partially based on the, previously released by Apple for the computer in 1983. As part of an agreement allowing to buy in Apple at a favorable price, it also used concepts from the computer, which former Apple CEO and other Macintosh team members had previewed. This operating system consisted of the ROM and the 'System Folder', a set of files that were loaded from disk. The name Macintosh System Software came into use in 1987 with System 5. Apple rebranded the system as Mac OS in 1996, starting officially with version 7.6, due in part to its program.

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That program ended after the release of in 1997. The last major release of the system was in 1999. Initial versions of the System Software run one application at a time. With the introduction of System 5, a extension called was added, which was later integrated into System 7 as part of the operating system along with support for. By the mid-1990s, however, contemporary operating systems such as, and had all brought, and multi-user capabilities to desktop computers, The Macintosh's limited and susceptibility to conflicts among that provide additional functionality such as networking or support for a particular device, led to significant criticism of the operating system, and was a factor in Apple's declining market share at the time.

After two aborted attempts at creating a successor to Macintosh System Software called and, and a spearheaded by in 1997, Apple replaced Mac OS with a new operating system in 2001 named. It retained most of the user interface design elements of the classic Mac OS, and there was some overlap of for compatibility, but the two operating systems otherwise have completely different origins and architectures.

The released in 2001 provided interoperability with Mac OS X. The name 'Classic' that now signifies the historical Mac OS as a whole is a reference to the, a that helped ease the transition to Mac OS X. Main article: The Macintosh project started in late 1978 with, who envisioned an easy-to-use, low-cost computer for the average consumer.

In September 1979, Raskin began looking for an engineer who could put together a prototype., a member of the team, introduced Raskin to, a service technician who had been hired earlier that year. Apple's original concept for the Macintosh deliberately sought to minimize the user's conceptual awareness of the operating system. Many basic tasks that had required more operating system knowledge on other systems could then be accomplished by mouse gestures and graphic controls on a Macintosh. This would differentiate it from its contemporaries such as, which use a consisting of tersely abbreviated textual commands. In January 1981, completely took over the Macintosh project.

Jobs and a number of Apple engineers visited Xerox PARC in December 1979, three months after the Lisa and Macintosh projects had begun. After hearing about the pioneering technology being developed at from former Xerox employees like Raskin, Jobs negotiated a visit to see the computer and development tools in exchange for Apple stock options. The final Lisa and Macintosh operating systems use concepts from the Xerox Alto, but many elements of the graphical user interface were created by Apple including the menu bar, pull-down menus, and the concepts of.

Unlike the, which uses 8 kB of system for (POST) and basic input/output system , the Mac ROM is significantly larger (64 kB) and holds key OS code. Much of the original Mac ROM was coded by, a member of the original Macintosh team. He was able to conserve precious ROM space by writing routines in code optimized with 'hacks,' or clever programming tricks. In addition to the ROM, he also coded the kernel, the, and some of the (DAs). The of the operating system, which represent and, were designed by, who later designed the icons for. And wrote the, as well as a number of Macintosh system utilities.

Apple was very aggressive in advertising their new machine. After it was created, the company bought all 39 pages of advertisement space in the 1984 November/December edition of magazine. Apple was so successful in its marketing for the Macintosh that it quickly outsold its more sophisticated predecessor, the. Apple quickly developed a product named, which allowed the Lisa to emulate Macintosh system software through System 3, by which time it had been discontinued as the rebranded. Many of Lisa's operating system advances would not appear in the Macintosh operating system until System 7 or later.

Architecture Compatibility Early versions of Mac OS are compatible only with -family Macintoshes. As Apple introduced computers with hardware, the OS was ported to support this architecture.

Mac OS 8.1 is the last version that could run on a 68k processor (the ). In systems prior to -based systems, significant parts of the system are stored in physical on the motherboard. The initial purpose of this is to avoid using up the limited storage of on system support, given that the early Macs have no (only one model of Mac was ever actually bootable using the ROM alone, the 1991 model). This architecture also allows 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 functioning disk drives, are communicated to the user graphically, usually with an icon or the distinctive bitmap font and a or a series of beeps. This is in contrast to and computers of the time, which display such messages in a mono-spaced font on a black background, and require the use of the keyboard rather than a mouse, for input.

To provide such niceties at a low level, early Mac OS depends on core system software in ROM on the motherboard, which also ensure that only Apple computers or licensed clones (with the copyright-protected ROMs from Apple) can run Mac OS. Mac clones. Main article: Several computer manufacturers over the years made that were capable of running Mac OS. From 1995 to 1997, Apple licensed Macintosh ROMs to several companies, notably,. These machines normally ran various versions of classic Mac OS.

Ended the clone-licensing program after returning to Apple in 1997. Support for Macintosh clones was first exhibited in System 7.5.1, which was the first version to include the 'Mac OS' logo (a variation on the original startup icon), and Mac OS 7.6 was the first to be named 'Mac OS' instead of 'System'. These changes were made to disassociate the operating system from Apple's own Macintosh models. File systems The Macintosh originally used the (MFS), a with only one level of folders. This was quickly replaced in 1985 by the (HFS), which had a true tree. Both file systems are otherwise compatible.

An improved file system named ('HFS+' or 'Mac OS Extended') was announced in 1997 and implemented in 1998. Files in most file systems used with, or other operating systems have only one '. By contrast, MFS and HFS give files two different 'forks'.

The data fork contains the same sort of information as a file in other file systems, such as the text of a document or the bitmaps of an image file. The contains other structured data such as menu definitions, graphics, sounds, or code segments that would be incorporated into a program's on other systems. An might consist only of resources (including ) with an empty data fork, while a might have only a data fork with no resource fork. A file could contain its text in the data fork and styling information in the resource fork, so that an application which doesn’t recognize the styling information can still read the raw text. On the other hand, these forks would provide a challenge to with other operating systems. In copying or transferring a Mac OS file to a non-Mac system, the default implementations would simply strip the file of its resource fork. Most contained only nonessential information in their resource fork, such as window size and location, but program files would be inoperative without their resources.

This necessitated such encoding schemes as and, which allowed a user to encode a dual-forked file into a single stream, or inversely take a single stream so-encoded and reconstitute it into a dual-forked file usable by Mac OS. Release history System 1, 2, 3, and 4. Original 1984 As part of Apple's goal of creating a computer with appliance-like simplicity, there is no explicit distinction made between the operating system software and the hardware it runs on. Because of this, early versions of the operating system do not have a distinct name. The software consists of two user-visible files: the System file, and the, an used for file management that also displays the.

The two files are contained in a folder directory labeled 'System Folder', which contains other resource files, like a, needed to interact with the System. Version numbers of the operating system are based on the version numbers of these two files.

System 1.0, 1.1, and 2.0 use a named (MFS). The Finder provides virtual folders that could be used to organize files, but these folders are not visible from any other application and do not actually exist on the disk. System 2.0 added support for and the newly introduced to use it. System 2.1 (Finder 5.0) introduced the (HFS) which has real directories.

This version was specifically to support the and only implements HFS in; startup and most floppy disks remain MFS 400 K volumes. System 3.0 (Finder 5.1) was introduced with the, officially implementing HFS, 800K startup drives, support for several new technologies including and, and Trash 'bulging' (i.e., when the Trash contains files, it gains a bulged appearance). System 4.0 was released with the and System 4.1 first shipped with the —these new machines required additional support for the first, the (ADB), internal hard drives and, on the Macintosh II, external color displays and the first processor. These releases can only run one application at a time, except for desk accessories, though special application shells such as Multi-Mac or Switcher (discussed under ) could work around this.

Visible changes are best reflected in the version number of the, where major leaps are found between 1.x, 4.x, 5.x, and 6.x. In the late 1990s, Apple retroactively gave these older releases a single name. Main article: System Software 6 (also referred to as 'System 6') is a consolidation release of the Macintosh system software, producing a complete, stable, and long-lasting operating system. Two major hardware introductions requiring additional support under System 6 are the processor and 1.44 MB debuting with the. Later, it would include support for the first specialized laptop features with the introduction of the. From System 6 forward, the Finder would have a unified version number closely matching that of the System, alleviating much of the confusion caused by the often considerable differences between earlier Systems. Main article: On May 13, 1991, System 7 was released.

It is a major upgrade over System 6, adding a significant overhaul, new applications, stability improvements and many new features. Its introduction coincides with the release of and provided support for the. The System 7 era saw numerous changes in the Macintosh platform including, the 68k to transition as well as the rise of, increasing use of and the explosion in popularity of the. One of the most significant features of System 7 is support, which previously had only been available as a third-party add-on. Accompanying this was a move to, necessary for the ever-increasing amounts of available to the Motorola 68030 CPU, and 68020 CPUs with a 68551 PMMU.

This process involves making all of the routines in OS code use the full 32-bits of a pointer as an address—prior systems used the upper 8 bits as. This change is known as being '32-bit clean'. While System 7 itself is 32-bit clean, many existing machines and thousands of applications were not, so it was some time before the process was completed. To ease the transition, the 'Memory' control panel contains a switch to disable this feature, allowing for compatibility with older applications. Another notable System 7 feature is built-in.

In System Software 6, this function was optional through the. System 7 also introduced, similar to on, that were introduced in later versions of Microsoft Windows, and in IBM.

Were enhanced by being moved to their own subfolder; a subfolder in the was also created for the. In System 7.5, Apple includes the, a previously third-party program which simplified the process of enabling and disabling extensions. The Apple menu, home only to desk accessories in System 6, was made more general-purpose: the user could now make often-used folders and applications—or anything else they desired—appear in the menu by placing aliases to them in an 'Apple Menu Items' subfolder of the System Folder. System 7 also introduced the following:, a for automating tasks;, supporting so-called 'true color' imaging, previously available as a system extension; and, an standard.

The Trash, under System 6 and earlier, empties itself automatically when shutting down the computer—or, if MultiFinder is not running, when launching an application. System 7 reimplements the Trash as a special hidden folder, allowing files to remain in it across reboots until the user deliberately chose the 'Empty Trash' command. System 7.1 System 7.1 is mainly a bugfix release, with a few minor features added. One of the major new features of System 7.1 was moving fonts out of the System file into the Fonts folder in the System Folder.

Previously a resource-copying utility such as ResEdit or Font D/A Mover was required for installing fonts. System 7.1 is not only the first Macintosh operating system to cost money (all previous versions were free or sold at the cost of the floppies), but also received a 'Pro' sibling (version 7.1.1) with extra features.

System 7.1.2 was the first version to support PowerPC-based Macs. System 7.1 also introduces the System Enablers as a method to support new models without updating the actual System file. This leads to extra files inside the system folder (one per new model supported).

System 7.5 System 7.5 introduces a large number of new features, many of which are based on shareware applications that Apple bought and included into the new system. On the newer PowerPC machines, System 7.5 may have stability problems partly due to a new memory manager (which can be turned off)and issues with the handling of errors in the PowerPC code (all PowerPC exceptions map to Type 11). These issues do not affect 68k-architecture machines. System 7.5 is contemporary with Apple's failed effort as well as the release of, which coincides with Apple's purchase of several system enhancements to include as new system features. Mac OS 7.6 Stability improved in PowerPC-based Macs with Mac OS 7.6, which dropped the 'System' moniker as a more trademarkable name was needed in order to license the OS to the growing market of third-party manufacturers.

Mac OS 7.6 required 32-bit-clean ROMs, and so it dropped support for every Mac with a processor, as well as the,. Mac OS 8.1 desktop Mac OS 8 was released on July 26, 1997, the same month became the CEO of Apple. It was mainly released to keep the Mac OS moving forward during a difficult time for Apple.

Initially planned as Mac OS 7.7, it was renumbered '8' to exploit a legal loophole and accomplish Jobs's goal of terminating third-party manufacturers' licenses to System 7 and shutting down the market. Mac OS 8 added a number of features from the abandoned project, while leaving the underlying operating system unchanged. A Finder was included; files could now be copied in the background.

The GUI was changed in appearance to a new shaded greyscale look named, and the ability to change the appearance themes (also known as ) was added with a new control panel (though Platinum was the only one shipped). This capability was provided by a new 'appearance' API layer within the OS, one of the few significant changes. Apple sold 1.2 million copies of Mac OS 8 in its first two weeks of availability and 3 million within six months. In light of Apple's financial difficulties at the time, there was a large grassroots movement among Mac users to upgrade and 'help save Apple'. Even some pirate groups refused to redistribute the OS. Mac OS 8.1 Mac OS 8.1 introduced an updated version of the named, which fixed many of the limitations of the earlier system and continued to be used in up until, when it was replaced with the. There are some other interface changes such as separating network features from printing, and some improvements to application switching.

However, in underlying technical respects, Mac OS 8 is not very different from System 7. Mac OS 8.5 Mac OS 8.5 focuses on speed and stability, with most 68k code replaced by modern code native to the PowerPC. It also improved the appearance of the user interface, although the theming feature was cut late in development. System Version Release Information Mac OS 8.0 first version to require a processor, dropping support for the remainder of the and other Macs. It also added support for the processor Mac OS 8.1 last Mac OS release to run on a processor, and it added support for on the and added support for the filesystem, also called Mac OS Extended Mac OS 8.5 first version to run solely on a processor, and it added built-in support for. It also added and added support for the Mac OS 8.5.1 added bug fixes to lessen system crashes Mac OS 8.6 included a new for improved performance and Multiprocessing Services 2.0 support, improved PowerBook battery life, and added support for the processor Mac OS 9.

Main article: Mac OS 9, the last major revision of the classic Mac OS, was released on October 23, 1999. It is generally a steady evolution from Mac OS 8. Early development releases of Mac OS 9 were numbered 8.7. Mac OS 9 added improved support for. It introduced an early implementation of multi-user support. Though not a true multi-user operating system, Mac OS 9 does allow multiple desktop users to have their own data and system settings.

An improved search engine added several new search plug-ins. Mac OS 9 also provides a much improved memory implementation and management. Was improved to allow and networking control. Mac OS 9 also makes the first use of the centralized to find and install OS and hardware updates.

Other new features included its on-the-fly software with and technologies, Remote Networking and packages, and much improved list of. Mac OS 9 also added some transitional technologies to help application developers adopt some features before the introduction of the new OS to the public, to help ease the transition. These included new APIs for the and the bundling of the library that apps could link against instead of the traditional API libraries—apps that were adapted to do this could be run natively on Mac OS X as well. Other changes were made beginning with the Mac OS 9.1 update to allow it to be launched in the within Mac OS X. The final update to the classic Mac OS was version 9.2.2, released on December 5, 2001.

System Version Release Information Mac OS 9.0 initial retail version of Mac OS 9 Mac OS 9.0.2 Mac OS 9.0.3 Mac OS 9.0.4 Mac OS 9.1 included with Mac OS 9.2 update for improved compatibility Mac OS 9.2.1 Mac OS 9.2.2 final release of classic Mac OS Transition to Mac OS X. The logos of, from through to (originally named 'Mac OS X' until 2012 and then 'OS X' until 2016) is Apple's current Mac operating system that officially succeeded the classic Mac OS in 2001. Although it was originally marketed as simply 'version 10' of Mac OS, it has that's largely independent of the earlier Mac OS releases.

The macOS architectural legacy is the successor to and the classic Mac OS legacy. However, unlike the classic Mac OS, it is a -based operating system built on and technology developed at from the late 1980s until early 1997, when Apple purchased the company, and its CEO returned to Apple. MacOS also makes use of the codebase and the kernel, and its core set of components is based upon Apple's.

An early version of the operating system, was released in 1999. It retains the 'platinum' appearance from the classic Mac OS and even resembles in places.

The desktop version, followed on March 24, 2001, supporting the new. Since then, of the operating system have been released. Mac OS X was renamed 'OS X' in 2012 and ' in 2016. Users of the classic Mac OS generally upgraded to Mac OS X, but it was criticized in its early years as more difficult and less user-friendly than the original Mac OS, for the lack of certain features that had not yet been reimplemented in the new OS, for being slower on the same hardware (especially older hardware), and for incompatibilities with the older OS. Because drivers (for printers, scanners, tablets, etc.) written for the older Mac OS were not compatible with Mac OS X, and due to the lack of Mac OS X support for older Apple computers, some Macintosh users continued using the older classic Mac OS for a few years after the original release of Mac OS X. Encouraged people to upgrade to Mac OS X by staging a mock for Mac OS 9 at 2002. Main article: versions of Mac OS X up to and including include a for running older Mac applications, the Classic Environment.

Originally codenamed the 'blue box', the environment runs a nearly complete Mac OS 9 operating system, version 9.1 or later, as a Mac OS X application. This allows applications that have not been ported to the to run on Mac OS X. This is reasonably seamless, though 'classic' applications retain their original Mac OS 9 appearance and do not gain the Mac OS X 'Aqua' appearance. Early PowerPC-based Macs shipped with Mac OS 9.2 as well as Mac OS X.

Mac OS 9.2 had to be installed by the user—it was not installed by default on hardware revisions released after Mac OS X 10.4. Most well-written 'classic' Mac OS applications function properly under this environment, but compatibility is assured only if the software was written to be unaware of the actual hardware and to interact solely with the operating system. The Classic Environment is not available on due to the incompatibility of with the hardware. Emulation 68k emulators.

See also: and Third-party Macintosh, such as, and, eventually made it possible to run the classic Mac OS on -based PCs. These emulators were restricted to emulating the series of processors, and as such most couldn't run versions of the Mac OS that succeeded 8.1, which required processors. Most also required a Mac ROM image or a hardware interface supporting a real Mac ROM chip; those requiring an image are of dubious legal standing as the ROM image may infringe on Apple's intellectual property. A notable exception was the commercial software product from Abacus Research & Development, the only product that used 100% reverse-engineered code without the use of Apple technology.

It ran extremely quickly but never achieved more than a minor subset of functionality. Few programs were completely compatible and many were extremely crash-prone if they ran at all.

Executor filled a niche market for porting 68k Mac applications to platforms; development ceased in 2002 and the source code was released by the author in late 2008. Emulators using Mac ROM images offered near complete Mac OS compatibility, and later versions offered excellent performance as modern x86 processor performance increased exponentially.

Apple included its own that ran seamlessly on all PowerPC-based versions of the classic Mac OS. PowerPC emulators In comparison with 68k-emulator development, support was difficult to justify due to the anticipated wide performance overhead of an emulated PowerPC architecture. This would later prove correct with the project, despite the availability of 7th and 8th generation processors employing similar architecture paradigms present in the PowerPC. Nevertheless, the PearPC emulator is capable of emulating the processors required by newer versions of the Mac OS. However, it is no longer maintained, and like many emulators, it tends to run much slower than a native would. Another PowerPC emulator is, which has been around since 1998 for on the PowerPC platform, but in 2002 was, and efforts began to port it to other platforms. Originally it was not designed for use on x86 platforms and required an actual PowerPC processor present in the machine it was running on similar to a.

Although it provides PowerPC processor support, it can run only up to because it does not emulate a. Other examples include ShapeShifter (by the same developer that created ), Fusion, and iFusion. The latter ran classic Mac OS with a PowerPC 'coprocessor' accelerator card. Using this method has been said to equal or better the speed of a Macintosh with the same processor, especially with respect to the series due to real Macs running in trap mode, hampering performance. Apple's was a PowerPC emulator for, but it did not support the classic Mac OS. Timeline Timeline of. ^ Linzmayer, Owen W.

Stanford University Libraries & Academic Information Resources. Archived from on July 21, 2010.

December 5, 2001. Archived from on April 21, 2006. Retrieved September 25, 2016. August 7, 2001. Retrieved September 25, 2016.

Gruman, Galen (November 1997). 'Why Apple Pulled the Plug'.

Retrieved November 28, 2009., retrieved May 10, 2010. Mike Tuck. Bruce Horn. Retrieved September 26, 2016. Mac OS 7.6 deserves some special mention.

The most obvious difference is the name change; this was for the Mac clone manufacturers, who weren’t making Macintoshes but “Mac OS Computers”. Apple Developer News. Archived from on May 12, 2008. Retrieved March 28, 2007. Retrieved 21 September 2015. Josh Burker (2002).

^ Kottwitz, Randal L. New York: MacUser Publications, Inc.: 11. Retrieved May 2, 2008. Retrieved 21 September 2015. November 10, 1988. Retrieved May 2, 2008.

^ Denny, Bob (November 1985). MacTech Magazine. Westlake Village, CA: MacTech. Retrieved May 2, 2008. Retrieved 21 September 2015. August 3, 1994.

Retrieved May 2, 2008. ^ Wiggins, Robert (March 1998). Martin Mazner.

Retrieved July 29, 2014. Retrieved 21 September 2015. Retrieved 21 September 2015. February 18, 2012. Retrieved July 29, 2014. Ean Houts (1994-09-05).

Apple has added a few features to spruce up the interface in System 7.5, although these have previously been available as utilities or shareware for quite some time. Steve Wood, “Busman’s Holiday: Disappearing Software,” (June 18, 1999), at. Beale, Steven (October 1997). 'Mac OS 8 Ships with No License Deal'. Macworld 14 (10): pp. Jeff Walsh (1997-07-28). August 8, 1997.

The latest word out in the Macwarez scene is that pirates shouldn't copy Apple's OS8—Mac's latest operating system—they should buy it, since Apple so desperately needs the money. December 5, 2001. Archived from on April 21, 2006. Retrieved February 23, 2017. July 15, 2004. From the original on July 22, 2010.

Retrieved September 6, 2014. Archived from (PDF) on May 30, 2009.

Retrieved February 5, 2016. Apple Computer (December 20, 1996). Archived from on January 16, 1999. Retrieved February 23, 2017. External links.

– Apple's official forum for Classic Mac OS. – A list of links to the history of GUIs. – A comprehensive guide to Mac OS releases prior to System 7.

– A site of shared by the creators of the first Macintosh. – Information on Macintosh systems from System 1 to System 7. – A web-based simulator. – A web-based simulator.

– A feature on vs.