System 1, also known as Mac System Software, was the original Macintosh operating system, and a part of the Classic Mac OS family, and ran on the 68K processor architecture. It was released on January 24, 1984 and replaced by System 1.1 on May 5, 1984. (Note: Eventually, the "Systems" were renamed "Mac OS") System 1 was originally released with the first Macintosh

Macintosh

The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...

, later named the Macintosh 128k

Macintosh 128K

The Macintosh 128K machine, released as the "Apple Macintosh", was the original Apple Macintosh personal computer. Its beige case contained a monitor and came with a keyboard and mouse. An indentation in the top of the case made it easier for the computer to be lifted and carried. It had a selling...

. System 1 introduced many features that would appear for years to come, some even still existing in Mac OS X. These features included a total lack of a command line, the Finder, and the menu bar. In addition to this, it popularized the graphical user interface

Graphical user interface

In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

 and desktop metaphor

Desktop metaphor

The desktop metaphor is an interface metaphor which is a set of unifying concepts used by graphical user interfaces to help users more easily interact with the computer. The desktop metaphor treats the monitor of a computer as if it is the user's desktop, upon which objects such as documents and...

.