Designers Guide to Mac OS X Tiger

For the most part, applications running in the Classic environment work just as if you were using them on a Mac booted into Mac OS 9 (Figure 7.12) instead of Mac OS X (Figure 7.13). I have even successfully used applications written for System 6 in the Classic environment. Since the Classic environment mimics the qualities of Mac OS 9 so well, you will experience the same problems with applications (see the sidebar "Mac OS 9's Fragile Foundation"). The upside is that if a Mac OS 9 application crashes, you don't have to restart your Mac; just relaunch the problem application.

Launching Mac OS 9 applications is easy: Just double-click the application's icon. If the Classic environment isn't already running, it will launch first, followed by your application. Your Desktop and the Finder look like Mac OS 9's Finder while you are using Classic applications. The Mac OS 9 rainbow Apple icon and the Multifinder are both good visual cues to look for. If you are working in an application that was developed for Mac OS 9, you will see the rainbow Apple menu icon (Figure 7.14) in the upper-left corner of your Desktop instead of Mac OS X's blue Apple menu icon (Figure 7.15), along with the Multifinder in the upper-right corner. In addition to showing all of your currently running Mac OS 9 applications, the Multifinder shows all of your running Mac OS X applications. Also, Classic applications use Mac OS 9's menu bar instead of Tiger's.