How Apple abandoned its own history to build the modern Mac operating system
The macOS we use today is not a descendant of the original Macintosh software. After years of failed attempts to modernize its aging system, Apple purchased NeXT in 1997. By integrating NeXT's advanced Unix-based technology, Apple finally replaced its outdated architecture with a stable, flexible foundation for the future.
By the mid-1990s, Apple’s original Macintosh System Software was struggling. Its single-user, cooperative multitasking architecture had reached its limits, and the interface felt increasingly obsolete. A massive internal project called Copland, intended to replace the system, collapsed under political infighting and was cancelled by 1996. Apple briefly considered buying BeOS, but ultimately chose to acquire NeXT, Inc. for $427 million in February 1997.
NeXT, founded by Steve Jobs after his 1985 departure from Apple, had developed NeXTSTEP, an object-oriented operating system based on the Mach kernel and BSD Unix. This technology provided the robust foundation Apple desperately needed. The transition was strategically difficult; developers were wary of Apple’s history of broken promises and resisted rewriting software for the new platform. To bridge the gap, Apple created Carbon, allowing existing Mac applications to run natively on the new Unix-based system, while the 'Classic' environment supported older software.
The resulting operating system, initially branded Mac OS X, featured the revolutionary Aqua interface. This marked a departure from the traditional Mac OS, introducing transparency, shadows, and the Dock. Development was complex, involving a shift from NeXT’s Display PostScript to an in-house engine called Quartz. While the system was initially criticized for being incomplete at its 2001 launch, it provided a stable base that Apple continuously refined through subsequent releases, eventually evolving from big-cat marketing names to California locations and, finally, a unified annual versioning system.
Source: MacOS version history
