I went ahead and documented the TPDD2 sector access protocol to the best of my ability. There are still two mystery commands that BACKUP.BA/FLOPPY.CO use before writing a sector from memory to disk. I simply lifted those two commands and use them, but I labeled them as Mystery Command #1 and #2. I posted the file here for anyone interested. This may help to finish the Sector Access page on Bitchin100.
Kurt
