Defines the command set extensions to facilitate operation of the sequential-access device type. This standard, implemented in conjunction with the requirements of the SCSI Architecture Model - 4 standard and the applicable clauses of the SCSI Primary Commands - 4 standard, fully specifies the standard command set for the sequential-access device type. The objectives of this standard are to provide the following: (a) permit an application client to communicate over a SCSI service delivery subsystem, with a logical unit that declares itself to be a sequential-access device in the PERIPHERAL DEVICE TYPE field of the standard INQUIRY data (see SPC-4); (b) define commands unique to the sequential-access device type; and (c) define commands to manage the operation of the sequential-access device type.