This standard defines the command set extensions to facilitate operation of SCSI media changer devices. The clauses of this standard@ implemented in conjunction with the requirements of the SCSI Architecture Model ?C 4 standard and SPC-4@ fully specifiy the standard command set for SCSI media changer devices. The objectives of the SCSI-3 Media Changer Commands ?C 3 standard are: a) to permit an application client to communicate with a logical unit that declares itself to be a media changer device in the PERIPHERAL DEVICE TYPE field of the INQUIRY command response data; and b) to define commands and parameter data to manage the operation of SCSI media changer devices. This standard makes obsolete the following commands and concepts from previous standards: a) the READ ELEMENT STATUS ATTACHED command; b) the MOVE MEDIUM ATTACHED command; and c) the attached media changer model. The set of SCSI standards specifies the interfaces@ functions@ and operations necessary to ensure interoperability between conforming SCSI implementations. This standard is a functional description. Conforming implementations may employ any design technique that does not violate interoperability. Figure 1 is intended to show the general structure of SCSI standards. Figure 1 is not intended to imply a relationship such as a hierarchy@ protocol stack@ or system architecture.