Dunno, it returns 0x20 which according the interrupt list is "controller failure".

Edit: It looks to have some non-standard use for bit 7 of the dor. It reads one sector then toggles that bit. It then looks for the FDC to be waiting for data (rather than sending it).

Edit: I bet bit 7 sets the tc line.

Last edited by crazyc; 05/10/13 08:48 PM.