Historically, the classic Mac OS used a form of memory management that has fallen out of favor in modern systems. Criticism of this approach was one of...

Mac OS 9 is the ninth and final major release of the classic Mac OS operating system for Macintosh computers, made by Apple Computer. Introduced on October...

the company's project to replace its "classic" Mac OS. That system, up to and including its final release Mac OS 9, was a direct descendant of the operating...

Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Macintosh family of personal computers...

Mac OS 8 is the eighth major release of the classic Mac OS operating system for Macintosh computers, released by Apple Computer on July 26, 1997. It includes...

of GS/OS on the Apple IIGS. It was rewritten completely with the release of Mac OS X in 2001. In a tradition dating back to the Classic Mac OS of the...

challenges that the classic Mac OS faced, such as problems with memory management. The current macOS is pre-installed with every Mac and receives a major...

Mac OS X Tiger (version 10.4) is the 5th major release of macOS, Apple's desktop and server operating system for Mac computers. Tiger was released to the...

macOS Catalina (version 10.15) is the sixteenth major release of macOS, Apple Inc.'s desktop operating system for Macintosh computers. It is the successor...

is the core Unix-like operating system of macOS, iOS, watchOS, tvOS, iPadOS, audioOS, visionOS, and bridgeOS. It previously existed as an independent open-source...

System 7 (later named Mac OS 7) is the seventh major release of the classic Mac OS operating system for Macintosh computers, made by Apple Computer. It...

MacsBug is a low-level (assembly language/machine-level) debugger for the classic Mac OS operating system. MacsBug is an acronym for Motorola Advanced...

either Mac OS X or the classic Mac OS. As the market has increasingly moved to the Cocoa-based frameworks, especially after the release of iOS, the need...

macOS Sierra (version 10.12) is the thirteenth major release of macOS (formerly known as OS X and Mac OS X), Apple Inc.'s desktop and server operating...

greater efficiency and the reduction of its overall memory footprint, unlike previous versions of Mac OS X which focused more on new features. Apple famously...

version of Mac OS as a whole (both Classic Mac OS and Max OS X) to use the Happy Mac icon. In 2002, with the release of version 10.2, the Happy Mac symbol...

Mac computers. This operating system replaced Apple's original Macintosh operating system, which has variously been named System, Mac OS, and Classic...

Keychain is a password management system developed by Apple for macOS. It was introduced with Mac OS 8.6, and was included in all subsequent versions...

MultiFinder is an extension for the Apple Macintosh's classic Mac OS, introduced on August 11, 1987 and included with System Software 5. It adds cooperative...

multiplying, and dividing, as well as memory keys. Scientific mode supports exponents and trigonometric functions. The macOS version of Calculator also has a...

running DOS (1983), Apple Macintosh running the Classic Mac OS (1985), AT&T UNIX PC (1985), Atari ST (1988), OS/2 (1989), Microsoft Windows (1989), SCO Unix...

OS X Lion, also known as Mac OS X Lion, (version 10.7) is the eighth major release of macOS, Apple's desktop and server operating system for Mac computers...

Macintosh Toolbox implements many of the high-level features of the Classic Mac OS, including a set of application programming interfaces for software...

is because Mac OS X replaced Mac OS 9's original virtual memory system with a more standard and less fragile implementation. The Classic Environment's...

OS 9 system folder is installed from which to run the Classic environment (although the 2005 Mac Mini cannot natively boot to Mac OS 9). As of Mac OS...

During the short time period when Mac OS X lacked labels, third-party software replicated the feature. In classic Mac OS versions 7 through 9, applying a...

changing their naming style, Mac OS 8. Planned as a modern successor to the aging System 7, Copland introduced protected memory, preemptive multitasking,...

OS X El Capitan (/ɛl ˌkæpɪˈtɑːn/ el KAP-i-TAHN) (version 10.11), also known as macOS El Capitan, is the twelfth major release of macOS (named OS X at the...

System. The original control panels in the earliest versions of the classic Mac OS were all combined into one small Desk Accessory. Susan Kare designed...

HFS Plus or HFS+ (also known as Mac OS Extended or HFS Extended) is a journaling file system developed by Apple Inc. It replaced the Hierarchical File...