Three Kinds of Programs: Cocoa, Carbon, Classic
Mac OS X was supposed to make life simpler. It was supposed to eliminate the confusion and complexity that the old Mac OS had accumulated over the years—and replace it with a smooth, simple, solid system.
In a few years, that's exactly what Mac OS X will be. For the moment, however, you're stuck with running three different kinds of programs, each with different characteristics: Cocoa, Carbon, and Classic.
The explanation involves a little bit of history and a little bit of logic. To take full advantage of Mac OS X's considerable technical benefits, software companies must write new programs for it from scratch. So what should Apple do—send out an email to the authors of the 18,000 existing Mac programs, suggesting that they throw out their programs and rewrite them from the bottom up?
At big companies like Microsoft and Adobe, such a suggestion would wind up on the Joke of the Week bulletin board.
Instead, Apple gave software companies a break. It wrote Mac OS X to let programmers and software companies choose precisely how much work they wanted to put into compatibility with the new system. The various levels include:
Do nothing at all (Classic). Let's face it: Software companies go out of business, unprofitable product lines are dropped, and shareware authors go off to law school. All of them leave behind orphaned programs that run only on the old Mac OS.
Your Mac OS X machine can still run this entire library of older software. When ...
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