As with many of our articles, the article on the PowerPC itself prompted comments from people who know more than I, so here are some quick notes that should help clarify the situation a bit more. First, it appears that Apple reps at PC Expo predicted that the release date of the first PowerPC machines will be in the spring of 1994, not January of 1994 as previously thought.
Wade Williams <williw1@mail.auburn.edu> paraphrased some comments from Jordan Mattson, the Marketing Manager for PowerPC Development Tools, in a recent developers' conference on America Online.
The emulation mode is "rock solid." Apple has not found an application that will break it with the exception of TMON, but since it's a low-level debugger and not an application, it doesn't really count. Since the emulation is complete at the Toolbox level, Control Panels and extensions should work as well.
The emulation will not include an FPU or MMU, as both would be incredibly slow. Someone asked about 3D-rendering packages that need an FPU, and Jordan felt convinced that they would be some of the first to go native since they need the extra speed.
So again, any application that requires an FPU won't work in emulation, just as they don't work on the Centris 610 sans FPU. Presumably, the lack of an MMU means that applications that have their own virtual memory scheme, such as Photoshop, may not work. I can only assume that the system software's VM will be supported for applications in native mode, but possibly not for those in emulation. However, he did not speak on this subject, so it is just my conjecture. Luckily, most applications that have their own virtual memory scheme will likely be ported to native mode quickly.
This is the most important point he made: the PowerPC computer, whatever it may be called, will run the Macintosh OS. Specifically, System 7.1 or whatever happens to be current. Some of it will run native, some in emulation. However, it will be the same system software (well, there will probably be a special "System 7.1 for PowerPC," but it will work the same).