1. A method of enabling storage of data using both SCSI-OSD protocol and block access SCSI protocol in a storage system, the method comprising steps of: receiving a command including a command descriptor block (CDB) from a host; determining whether the CDB contains a SCSI-OSD operation code and a SCSI-OSD service action code; when the CDB contains both the SCSI-OSD operation code and the SCSI-OSD service action code, a logical unit is selected from a list of logical units prepared for storage of data using the SCSI-OSD protocol; and when the CDB does not contain both the SCSI-OSD operation code and the SCSI-OSD service action code, a logical unit is selected from a list of logical units prepared for storage of data using the block access SCSI protocol.