Classic, Carbon and Cocoa

Classic, Carbon and Cocoa
Mac Tip #170/27-Oct-2004

Applications is another word for programs or software; they include AppleWorks, Microsoft Word, Graphic Converter, Internet Explorer and thousands of others. Each application depends on the Operating System (OS) to be able to do its job.

It’s as if the OS is a servant to whom the software can give orders: “Haul that barge! Tote that bale!”

When Apple moved from using the good old Mac OS to the new Mac OS X it was like getting a brand new servant, trained in a new and different tradition and speaking another language.

The trusty old servant may have been speaking Ancient Latin while the new one is speaking modern English. (My apologies to those readers for whom English isn’t their first language.) Things no longer work the same.

Classic

If you try to use an old version of something like Microsoft Word (eg Word 2001) then Mac OS X has to call up Classic in order to run it. Classic is Mac OS 9 running under Mac OS X. It’s as though you have to get the old servant back to translate your orders to the new servant.

Carbon

The new servant (Mac OS X) is also a lot more clever than the old one (OS 9).

Some software writers have modified their programs to be “Carbon” applications. These programs bridge both worlds and can run in both OS 9 and OS X. They can use a lot of the new skills of the new servant, but they still don’t really speak modern English. AppleWorks is an example of a Carbon application.

Cocoa

Cocoa applications are written for Mac OS X and should be able to take full advantage of all the new features of the Operating System. These ones are using the new servant with its modern language and all its new skills, but they can’t run in Classic. An example is Apple’s own TextEdit.

If you’ve read this far, you’re probably saying “So what?”. Well, in some Tips I’ll be mentioning that you can do certain things, but you might find they don’t work if you’re using a Carbon application. That’s why last week’s Tip on using the Services menu doesn’t work if you’re using AppleWorks — it’s a Carbon application, not a Cocoa application. Just try it in TextEdit and magically it will work.

You don’t need to really know or understand all this stuff about Classic, Carbon and Cocoa, but it is helpful as background knowledge.