“At last year’s WWDC, Steve Jobs announced that Leopard would support 64-bit computing across the board: not only on the Unix command line as in Tiger, but also in Carbon and Cocoa. But… During yesterday’s keynote, Jobs only mentioned Cocoa would get the 64-bit treatment, with Carbon missing in action. Carbon is the Application Programmer Interface (API) that made the transition from OS 9 to OS X possible, and although it’s not the latest and greatest (that would be Cocoa), Carbon is still holding its own—even Apple uses it to power some of its own applications. Sources tell Ars that not mentioning Carbon was no oversight: apparently, Apple has decided to scrap the intended 64-bit support in Carbon,” Iljitsch van Beijnum reports for Ars Technica.
“Although we can still look forward to 64-bit Cocoa applications in Leopard, this development means that third-party developers, especially those with cross-platform products, will be less inclined to support 64-bit computing in their applications. Doing so would require removing all references to Carbon,” van Beijnum reports.
Full article here.
More about Mac OS X Leopard’s 64-bit technology: http://www.apple.com/macosx/leopard/technology/64bit.html