Prior to its release, Apple had three series of command-line driven terminal computers known as the Apple I, Apple II and Apple III. The original Macintosh was released in January 1984, and was one of the first systems to pioneer the graphical user interface (GUI). The series was rebranded from Mac OS X to OS X in 2012 and to its modern name macOS in 2016. This series of the operating system is also the basis for iOS as well as its other siblings in Apple's product lineup. Instead of being based on the Classic Mac OS, the series traces its roots back to NeXTSTEP which itself is derived from UNIX.
The family is separated into two distinct series: Although there are certain 'regular' PCs that can run the operating system (know as 'Hackintoshing') it is highly controversial due to violating Apple's end-user license agreement and being notoriously inconsistent in its results.
MacOS is a family of operating systems developed by Apple and exclusively available to Apple's own family of personal computers known as Macintosh (or Mac for short).
