I once built a controller that let a CP/M machine (hosted by a Z80) read and write Apple ][ floppy diskettes. I made the controller hardware by purchasing an actual Apple controller board and mounting that on to an S100 proto board. A few additional chips interfaced the S100 I/O space to the Apple bus of the floppy disk controller board. The code that it took to operate the board was not overly magical, but it was difficult to make. I remember working for several weeks on the implementation just to be able to reliably read and write Apple sectors.

As I write this I now remember talking about all this before in this thread...

http://www.8052.com/forum/read.phtml?id=45202

and again here...

http://www.8052.com/forum/read.phtml?id=43868

Michael Karas