What is Rosetta
From Wikipedia
Rosetta is a lightweight dynamic translator for Mac OS X distributed by Apple.
It enabled applications compiled for the PowerPC family of processors to run on Apple systems that use Intel processors. Rosetta was based on Transitive Corporation's QuickTransit technology,[1] and was a key part of Apple's strategy for the transition of their Macintosh line from PowerPC to Intel processors as it enables pre-existing Mac OS X software to run on the new platform without modification.
Rosetta has no GUI, leading Apple to describe Rosetta as "the most amazing software you'll never see".[2]
The name is likely a reference to the Rosetta Stone, the discovery of which made it possible to comprehend and translate Egyptian hieroglyphs.
In Mac OS X v10.6 ("Snow Leopard"), Rosetta is not included by default but there is an option in the installer for the user to include it or it could be automatically downloaded by the system if needed at a later time.
Mac OS X v10.7 ("Lion") does not include or support Rosetta. Therefore, Lion drops support for all PowerPC applications.[3]
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