I get an error when I attempt to FAT format them on the AMIGA...."Disk is not Validated. I can format them to FFS alll day long on the Amiga...weird I say!
I'm at the point of thinking I'm not getting a true FAT16 filesystem on the ZIP Disk after I format it on my Win7 PC..
Then there is the problem

Ok, you need to get the dos driver working... It's been too long for me to remember the specifics of this
