The Macintosh Operating System (known as the Mac OS Classic) is the name for a standard operating system for Macintosh computers produced by Apple Inc. The first version was released in 1984. Even before version 7.6, it was just called System (eg: System 4, System 7), from version 7.6 onwards is now called Mac OS. It was replaced by MacOS X, a new operating system rebuilt from Unix BSD, preserving some graphics from the old system.
It was the second operating system to use a GUI (after the Xerox Alto prototype, developed at Xerox PARC), and the first graphics system widely used on computers to use icons to represent computer items, such as programs, folders and documents. He was also a pioneer in the dissemination of the Desktop concept, with a Work Desk with icons of documents, folders and a trash can, in analogy to the office environment.
At first, folders were created by renaming an "Empty Folder" that was always at the root of the disk. As of System 2.0, the system was modified, with the inclusion of the "New Folder" command in the Finder's File menu.