The Mac 68K emulator was a software emulator built into all versions of the Mac OS for PowerPC. This emulator permitted the running of applications and system code that were originally written for the 680x0 based Macintosh models. The emulator was completely seamless for users, and reasonably seamless for programmers. It is thought that this aspect of the Mac OS is the first time that such a dual hardware architecture operating system had ever been successfully implemented.
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