Rosetta is based on QuickTransit technology. It was initially included with Mac OS X v10.4.4 'Tiger', the version that was released with the first Intel-based Macs, and allows many PowerPC applications to run on Intel-based Mac computers without modification. This allows lines of 68k and PowerPC code to be interspersed within the same fat binary.Īpple released the first version of Rosetta in 2006 when it began switching the Macintosh line from the PowerPC to the Intel processor. This means that the nanokernel is able to intercept PowerPC interrupts, translate them to 68k interrupts (then doing a mixed mode switch, if necessary), and then execute 68k code to handle the interrupts. This emulator takes advantage of features built into the PowerPC processors, and accesses the very lowest levels of the OS, running at the same level as – and tightly connected to – the Mac OS nanokernel. When it introduced its first PowerPC systems, Apple included software in System 7.1.2 and later versions of the operating system to emulate a 68000-series system.

Each transition has rendered software produced for the earlier architecture incompatible with the new one, creating a need for software allowing the newer platform to emulate the previous one. Īpple has used four series of CPU architectures in its Macintosh line of computers: the Motorola 68000 series, the PowerPC series, the Intel Core series, and its own series of ARM-type processors. The second version, introduced in 2020 as a component of macOS Big Sur, is part of the Mac transition from Intel processors to Apple silicon, allowing Intel applications to run on Apple silicon Macs. The first version of Rosetta, introduced in 2006 as a component of Mac OS X Tiger, was part of the Mac transition from PowerPC processors to Intel processors, allowing PowerPC applications to run on Intel-based Macs. The name 'Rosetta' is a reference to the Rosetta Stone, the artifact which enabled translation of Egyptian hieroglyphs. It gives developers and consumers a transition period in which to update their application software to run on newer hardware, by 'translating' it to run on the different architecture. for macOS, an application compatibility layer between different instruction set architectures. Rosetta is a dynamic binary translator developed by Apple Inc.

PowerPC binary translation (original version) PowerPC application (Microsoft Word for Mac 2004) running on Mac OS X for Intel in Rosetta

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