Dear Aunt TUAW: Help me agitate for Lion Rosetta

Dear Aunt TUAW,

Apple should SELL Rosetta in the App store. Please remind folks that they can complain about Lion most effectively by writing to Apple's feedback page.

Your loving nephew,

Dave Y.

Dear Dave,

Unfortunately, it's not quite as simple as that. Rosetta represents far more than a simple app. Auntie is not an expert on these matters so she turned to Uncle Mike for clarification. Here's how he explained things.

The Power PC (PPC) backwards-compatibility provided by Rosetta was created by an entire OS of "fat" frameworks, combining support for PPC as well as Intel. Apple described it this way:

New applications bearing the Universal symbol will run natively on both Intel- and PowerPC-based Mac computers. What about the applications you already own? Enter Rosetta. You'll never see it, you'll never configure it, you'll never have to think about it. It's built into Mac OS X to ensure that most of your existing applications live a long and fruitful life.

Rosetta was pretty awesome. It invisibly translated and executed code so old apps could continue to run on new hardware.

Here's what the QuickLook framework looks like under Snow Leopard

% file QuickLook
QuickLook: Mach-O universal binary with 3 architectures
QuickLook (for architecture x86_64): Mach-O 64-bit dynamically linked shared library x86_64
QuickLook (for architecture i386): Mach-O dynamically linked shared library i386
QuickLook (for architecture ppc7400): Mach-O dynamically linked shared library ppc

And under Lion

% file QuickLook
QuickLook: Mach-O universal binary with 2 architectures
QuickLook (for architecture x86_64): Mach-O 64-bit dynamically linked shared library x86_64
QuickLook (for architecture i386): Mach-O dynamically linked shared library i386

Notice how the new frameworks don't have any PPC architecture? Even though Snow Leopard wouldn't run on PPC hardware, it still provided this backwards compatibility for PPC-compiled apps to link to, which was in turn translated in real time to the native instruction set.

Apple can be pretty brutal when it comes to policy decisions. From the floppy drive to Rosetta, it has a vision of the future that it moves forward to meet. It never hesitates to cut away the anchors of the past.

Lion has dropped support for all PPC applications, creating a leaner meaner cleaner operating system that isn't tied back to archaic processors. But that means Apple can't just sell Rosetta in App Store.