I bet more than a few of you are confused as to the difference between Rhapsody, the Yellow Box, and the Blue Box, and its relationship with the forthcoming MacOS 8. Don Crabb, a regular columnist for MacWeek, produced a really clear technical explanation for how this will all work in his May 20 Mac Manager column, "The way it will work." To summarize, here's what he discovered.

There will be four versions of Rhapsody: (1) Rhapsody for the PowerPC, (2) Rhapsody for Intel, (3) Yellow Box for the MacOS, and (4) Yellow Box for Windows.

1. Rhapsody for the PowerPC will be the full-fledged new operating system (OS) we're all waiting for. It will include two pieces, now called the Yellow Box and the Blue Box. The Yellow Box will run all of the new applications with all of the features we've been waiting for, protected memory for each application, preemptive multitasking, and all the other buzzwords you've heard about which will make the new OS so great.

The Blue Box will be the environment that runs the current versions of Mac software. This special area of memory running under Rhapsody will not provide any of the new OS's new features. It will simply be a way to continue to use your old software under the new operating system. As you upgrade your old software to Yellow Box versions over time, you'll gain the benefits when those applications begin running in the Yellow Box.

How will this look on your screen? That's unclear. The old applications may be running in a separate window with the traditional menu bars appearing across the top of the window, or the more elegant solution of making them appear normally across the top of your screen may be selected. What is clear is that this environment will NOT be an emulator. It will be running the actual MacOS operating system controlling the old applications at their normal full speed. So the Blue Box will just be the current MacOS running today's applications in a special memory area under Rhapsody.

2. Rhapsody for Intel will be the Yellow Box running on an Intel PC. It will run applications written for Rhapsody for the Mac, but will not have the Blue Box to run today's MacOS applications. This will be great for software developers, because they will be able to write their application once and it will be able to run on all PowerPC and Intel chip based personal computers.

3. Yellow Box for the MacOS will run on the MacOS and permit new applications written for the Yellow Box to run under the older operating system. You won't get the strengths of Rhapsody, such as protected memory or multitasking, but you will be able to use the application.

4. Yellow Box for Windows will allow these new applications to run under Windows, again subject to the weaknesses in that operating system.

I hope this helps.

- Dave Marsh