System 1

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System 1
A version of the Mac OS operating system
Apple Macintosh Desktop.png
The original System 1 desktop
Developer Apple Computer
Source model Closed source
Released to
January 24, 1984; 32 years ago (1984-01-24)
Latest release 1.1 / May 5, 1984; 31 years ago (1984-05-05)
Kernel type Monolithic
License Proprietary
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, and ran on the Motorola 68000 microprocessor. It was released on January 24, 1984 along with the original Macintosh and was replaced by System 1.1 on May 5, 1984.[1]


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 amount of RAM and the lack of an internal hard disk in the original Macintosh, there was no multitasking with multiple applications, although there were small applications that could run while an application was loaded. Also, items in the Trash were permanently deleted when the computer was shut down or an application was loaded (quitting the Finder).


  1. ^ Mesa, Andy. "The Early Mac OS". The Apple Museum. Retrieved 2015-02-15.