Prior to using these functions a handle to the drive has to be obtained. This
is done with the
dio_open function. After use, the handle should be
released with the
dhandle_t __fastcall__ dio_open (driveid_t drive_id);
drive_id specifies the drive to access, with 0 being the first
disk drive, 1 the second, and so on.
unsigned char __fastcall__ dio_close (dhandle_t handle);
Closes a handle obtained by
dio_open. Returns status code.