How did they make the change between processors without a hitch?

[shibboleth]

Here's a quote from an Apple Insider article: "They both pulled off an immensely complex move of processors — with Jobs taking Apple from PowerPC to Intel — and both did it so well that it's easy to forget what a task it was."

What would this task entail? How did they do it so well?

 

[maflynn]

The issue us that going from processor family to another means existing code would not work. The flawless nature was producing Rosetta that allowed PPC code to run on intel without a huge performance penalty. They did it again with Rosetta 2, allowing x86 code to execute on ARM processors.

Rosetta and Rosetta 2 are bridging technology allowing the legacy code to run on the new processors as Apple pushed the developers to develop native (for the new processor) apps