Mac OS 7 was a major change from the earlier System Software, introducing integrated multitasking, a revamped desktop, networking, and transitioning the name from "Macintosh System Software" To "MacOS'. It was followed by MacOS 8.x.

Running Mac OS 7.x requires a Motorola 68000 based Macintosh, a supported model of Power PC based Macintosh (7.1 or later) or one of the following emulators:

Mini vMac - Runs MacOS 1.1-7.5.5, emulates a black and white Motorola 68K based Mac Plus

Basilisk II - Runs MacOS 7.x-8.1, emulates later color Motorola 68k based Macs.

SheepShaver - Runs MacOS 7.5.2-9.0.4, emulates a Power PC based Macintosh.

Minor changes, bug fixes, and API enhancements. 7.1.2 is the first to support PPC.