It is very important to note that just because your drive may be made by Sony, it may not be one of these drives. It could still be SCSI or IDE. Only use this section if you have model numbers CDU31, CDU33, or 535.
To identify these drives, you must use the part numbers on the drives themselves or in the documentation that came with it. You may also find them when watching the drivers load under DOS or other OS's.