Back in 2005 at WWDC, Steve Jobs revealed in dramatic taste, how OS X was developed to be processor agnostic from its inception. Early hints of this can be found in developer previews of OS X, which let developers target either PowerPC or Intel development. Even ancestor of OS X, NextStep and OpenStep were available for Intel x86. My interest though surrounds Apple's maintenance of OS X, the marketed product on Intel in secret. There is a story on Quora posted by a Apple developers wife, who hacked together a working version on Intel for 18 months, without even Apple knowing it seems. This eventually became known as Marklar, but was never officially acknowledge due to secrecy. When Steve said every version of OS X was recompiled for Intel, was this just dramatics or actual behind the scenes strategy? Because this seemed to have been a one man, experimental project; on home machines that he suggested to his program manager at Apple; and wasn't something of interest to Apple until higher level folks such as Bertrand Serlet, Steve Jobs saw a fully working system running it. Also, there is not much detail as to whether this was the 'when you see it, you want to lick it' Aqua based OS X or maybe a proof of concept command line/verbose loading OS X on x86 hardware. What is known though, that the project was certainly legitimized around 'Jaguar', especially the story of how much lock down went into it. I do believe what was initially skunkworks, became a full team compiling Panther (and Tiger which we got to saw and use) on Intel. What would be interesting is, if it were possible to get ahold of those 10.0, 10.1, 10.2 and 10.3 releases of OS X on Intel. I am thinking of contacting Kim Scheinberg for more information and Craig Federighi if he would be willing to give me copies to play with.