This SORT of thing was pretty common copy protection on Ataris. "I'm told" the 1050 "dual density" disk drives had a potentiometer on it that could be adjusted

This SORT of thing was pretty common copy protection on Ataris. "I'm told" the 1050 "dual density" disk drives had a potentiometer on it that could be adjusted to vastly speed up or slow down the drive. That, combined with software to tell "you" when, could be used to purposely mis-copy sectors to a destination floppy to replicate the effect.