DOS_GET_POSITION
Get the file pointer
Get the file pointer
Set the file pointer
Get the end of file (EOF) position
Get current cache/ramdisk location
Rebuild the sector cache and RAM disk
Write any pending data to this drive
Change access mode of an open file
Set a files attributes
Open drive as a single file
Enable/disable disk error messages
Point at XDPB for this drive
Map drive B to unit 0 or 1