From the Reader Mail column in this month's issue of Tips & Tricks (August 2005):
360 Degrees of Compatibility
I read in your July issue that the new Xbox 360 will be backward-compatible with the original Xbox games. But then I saw on some Web sites that only the "best-selling" Xbox games will play on the Xbox 360. So which is it?
Francis Eliopolous
Virginia Beach, VA
-It seems that the Xbox 360 does not have enough of the native hardware of the original Xbox to promise 100% compatibility with standard Xbox titles. Therefore, some of the functions of the older machine may be emulated by software running on the new hardware. When that happens, the only way to guarantee that every Xbox game will play correctly is to actually play them all, all the way through, on the Xbox 360. It'll take time to go through all of the existing Xbox games and get them running properly, so Microsoft plans to start with the games that you're most likely to want to play, like Halo and Halo 2.
If a particular game doesn't work perfectly on the new system, it may require a software patch or driver to be installed on the Xbox 360. Some of these "fixes" may even be built into the hardware at launch, for the games that have been fully tested for compatibility; others may require a small file to be downloaded from Xbox Live. So it is possible that the Xbox 360 will eventually be compatible with all of the original Xbox titles, but it might take a while before you can bust out the more obscure stuff like Sneakers or Tao Feng: Fist of the Lotus.