Apple CEO Steve Jobs "thought different" once again during his Worldwide Developers Conference (WWDC) keynote speech this morning - Apple is moving to Intel.

Apple has invested significant time in building the bomb, he said: "I can confirm the rumours that every release of Mac OS X has been compiled for PowerPC and Intel. This has been going on for the last five years", he said.

While the system running Mac OS X - which relies on the already cross-platform Darwin core of OS X - remains a mystery, Apple confirmed that the demonstration version of Mac OS X on Intel relied on a 3.6GHz Pentium 4-processor powered system. Dashboard, Spotlight, iCal, Mail, Safari and iPhoto were all shown working on this test system.

The secret life of Mac

"Mac OS X has been leading a secret double life. There have been rumors to this effect", he said. "We've had teams working on the just in case scenario", he confirmed.

With five years experience behind the company, Jobs took pains to reassure developers the transition would be surprisingly painless - and that both Intel and PowerPC-based processors would be supported for a "long time to come".

As proof, Apple invited Wolfram Research developer Theo Grey onstage. Apple invited Grey to visit Cupertino on June 1 to port Mathematica to the new processor. Grey said it took just two hours - and Apple's secretly-developed "Universal binaries" to complete this port.

"We're talking about 20 lines of code out of millions from a dead cold start", he said. A

Rosetta revealed

Apple has developed emulation software to ease this process, which is called "Rosetta". Rosetta lets PowerPC applications work on Intel-powered Macs. Jobs showed PowerPC applications Quicken and Photoshop CS 2 in action on the new Intel Macs.

“So that is Rosetta, Jobs said. “These PowerPC apps just run. And that’s what we’re going to have for our users, because every app isn’t going to be there for our users on day one.”

Massive industry support

Intel CEO Paul Otellini climbed the stage with Jobs, calling Apple "the most innovative computer company in the world". In recent weeks, Intel has admitted to twenty-years of wooing Apple.

Microsoft's general manager of Microsoft’s Mac Business Unit Roz Ho also joined Jobs on stage, promising the Redmond software giant's support for Apple's new plan: “We plan to create future versions of Microsoft Office for the Mac that support both PowerPC and Intel processors,” Ho said.

Adobe CEO Bruce Chizen lent his company's support: “We think this is a really smart move on Apple’s part and plan to create future versions of our Creative Suite for Mac that support both PowerPC and Intel processors." He added that Adobe would not have existed if it had not been for Apple.

Speaking to Macworld during Adobe Live in London recently, Adobe vice president Bryan Lamkin alluded to the Mac to Intel shift. Speaking just days after the Wall Street Journal first revealed the move, Lamkin avoided discussing Apple's move, but said: "Can you think of a company better-suited than Adobe to recompile its applications for this?"

He explained that Adobe's applications already offer feature-parity between Mac and Windows systems on different processors. Adobe is able to achieve this because of the way it builds its applications. It uses platform-independent code for much of the applications it builds, while exercising platform-specific code designed to make applications work on multiple platforms - and to exploit each platforms inherent advantages.