Mac OS

The family of Macintosh operating systems developed by Apple Inc. includes the graphical user interface-based operating systems it has designed for use with its Macintosh series of personal computers since 1984, as well as the related system software it once created for compatible third-party systems. In 1984, Apple debuted the operating system that is now known as the 'Classic' Mac OS with its release of the original Macintosh System Software. The system, rebranded 'Mac OS' in 1996, was preinstalled on every Macintosh until 2002 and offered on Macintosh clones for a short time in the 1990s. Noted for its ease of use, it was also criticized for its lack of modern technologies compared to its competitors. The current Mac operating system is macOS, originally named 'Mac OS X' until 2012 and then 'OS X' until 2016. Developed between 1997 and 2001 after Apple's purchase of NeXT, Mac OS X brought an entirely new architecture based on NeXTSTEP, a Unix system, that eliminated many of the technical challenges that the classic Mac OS faced. The current macOS is preinstalled with every Mac and is updated annually. It is the basis of Apple's current system software for its other devices – iOS, watchOS, tvOS, and audioOS. Prior to the introduction of Mac OS X, Apple experimented with several other concepts, releasing different products designed to bring the Macintosh interface or applications to Unix-like systems or vice versa, A/UX, MAE, and MkLinux. Apple's effort to expand upon and develop a replacement for its classic Mac OS in the 1990s led to a few cancelled projects, code named Star Trek, Taligent, and Copland. Although they have different architectures, the Macintosh operating systems share a common set of GUI principles, including a menu bar across the top of the screen; the Finder shell, featuring a desktop metaphor that represents files and applications using icons and relates concepts like directories and file deletion to real-world objects like folders and a trash can; and overlapping windows for multitasking. The 'classic' Mac OS is the original Macintosh operating system that was introduced in 1984 alongside the first Macintosh and remained in primary use on Macs through 2001. Apple released the original Macintosh on January 24, 1984; its early system software was partially based on the Lisa OS and the Xerox PARC Alto computer, which former Apple CEO Steve Jobs previewed. It was originally named 'System Software', or simply 'System'; Apple rebranded it as 'Mac OS' in 1996 due in part to its Macintosh clone program that ended a year later. Classic Mac OS is characterized by its monolithic design. Initial versions of the System Software run one application at a time. System 5 introduced cooperative multitasking. System 7 supports 32-bit memory addressing and virtual memory, allowing larger programs. Later updates to the System 7 enable the transition to the PowerPC architecture. The system was considered user-friendly, but its architectural limitations were critiqued, such as limited memory management, lack of protected memory and access controls, and susceptibility to conflicts among extensions.