This one I am unsure of, but I do know I had an external floppy drive which seemed to only have a controller board, and it was connected to a PC floppy drive, but not entirely true. I connected a PC floppy drive, and it did not work. And yes, i checked for the HD, DD holes, and still no go..
I think some drives you can actually change the jumpers so the Amiga can work with it..
