* Dissassembly of the code indicates it uses an I/O port &f0e0, and sends the data 0,1,2 or 3. It is not clear the function or the exact decoding of this port.
* It is restricted to loading/saving using DATA format disc.It uses sectors &c1-&c8 and reads/writes this entire range on each track in a multi-sector operation. DATA format has 512 bytes per sector, so sectors &c1-&c8 is 4K. So it reads 4K from each track.
Unanswered questions: