MacOS

macOS - is the UNIX-based operating system. macOS is created by Apple. The "classic" Mac OS was introduced in 1984 alongside the first Macintosh and remained in primary use on Macs until the introduction of Mac OS X in 2001.

First ever version is released on January 24, 1984 as a System 1. It is renamed to Mac OS in version 7.6. Mac OS 7 was the longest developed version to have only major number since it's release in almost 6 years, after that Mac OS X beats 7 in 2007. Had similar interface as nowaday's Windows.

The term "Classic" Mac OS gets since Apple renames OS X to macOS in 2016, so it shouldn't confuse consumers to the former.

macOS is created in 2001. It was developed in earlier than 1999, and back in March 16, 1999 Apple releases Mac OS X Server 1.0, which was the first way to Mac OS X era. Then they releases public beta in September 13, 2000, revealing Dock, menu bar, new interface. Tiger is the first release to adopt Intel processors and x86 archeticture in general. Mac OS X is released in March 24, 2001 as a version 10.0, then renamed to OS X in version 10.8, then to macOS in 10.12. While Microsoft, and majority of OS creators hides their codenames, Apple publics their codenames in macOS, naming a new codename every version, while they calling macOS versions 10.0-10.8 after big cats, since 10.9 they naming after major California landmarks. Last versions of macOS is released in early October, with macOS 10.15 released in October 7, 2019.

In June 22, 2020, macOS Big Sur (version 11) was revealed at the WWDC 2020 and were released to developers prior to the announcement. Big Sur is notable to support Apple M chips, Apple-designed processors marketed as Apple Silicon. macOS Big Sur was the first version to support ARM.