Related to that there are many different copy protection schemes and other formats for writing the data that don't result in circular tracks. Lots of old comput

Related to that there are many different copy protection schemes and other formats for writing the data that don't result in circular tracks. Lots of old computers addressed the drive at such a low level that it was possible to directly control the head between tracks, and control the rotational speed of the disk. For example there's this project that reads stranger formats http://cowlark.com/fluxengine/ http://cowlark.com/fluxengine/