System 1

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For other uses, see System One.
System 1
Part of the Mac OS family
Apple Macintosh Desktop.png
The original System 1 desktop
Apple Computer
Release to
January 24, 1984; 30 years ago (1984-01-24)[citation needed]
Latest stable
1.1 (May 5, 1984; 30 years ago (1984-05-05))[citation needed]
Source model Closed source
License Proprietary
Kernel type Monolithic
Succeeded by System 1.1, then System 2
Support status

System 1, also known as Macintosh System Software was the original Macintosh operating system. It is a part of the Classic Mac OS family. It ran on the 68K processor architecture of the time. It was released on January 24, 1984 along with the original Macintosh (aka Macintosh 128K) and replaced by System 1.1 on May 5, 1984.


This operating system introduced many features that would appear for years to come, some even still existing in OS X, and a few existing in other graphical operating systems such as Microsoft Windows.

The features of the operating system included a total lack of a command line interface (which was included in Microsoft's Windows 1.0 introduced in 1985), Finder, and the menu bar. In addition to this, it popularized the graphical user interface and desktop metaphor, which was used under license from Xerox PARC.

Due to the limited RAM of early computers, there was no multitasking with multiple applications, however there was small applications that could run while an application was loaded. Also, the Trash lost the contents when the computer was shutdown or an application was loaded (closing Finder).