System 7.0

System 7.0 was released in May 1991. System 7 (codenamed "Big Bang" and "Furnishings 2000", retroactively referred to as Mac OS 7) is a single-user graphical user interface-based operating system for Macintosh computers. It was introduced on May 13, 1991 by Apple Computer.[1]  It succeeded System 6, and was the main Macintosh operating system until it was succeeded by Mac OS 8 in 1997. Features added with the System 7 release included virtual memory, personal file sharing, QuickTime, QuickDraw 3D, and an improved user interface.

"System 7" is often used generically to refer to all System 7.x versions. With the release of Mac OS 7.6 in 1997, Apple officially renamed the operating system "Mac OS", a name which had first appeared on the boot screen of 7.5.1. System 7 was developed for Macs that used Motorola's 68k line of processors, but was ported to the PowerPC after Apple adopted the new processor.