HP Surestore 80fx Optical Drive and Library SCSI-2 Command Reference - Page 166

SCSI-2 Drive Commands NOTE NOTE SCSI-2 Drive Command Set Read (Group 5) Command (A8H) DPO A Disable Page Out bit of 1 instructs the target not to store readahead data in cache after the read data has been transferred to the initiator. A DPO bit of 0 instructs the target it may store readahead data in the cache after the read data has been transferred to the initiator. The DPO bit is ignored in 9.1 and 5.2 Gbyte capacity drives. FUA Rel Adr Transfer Length PBA A Force Unit Access bit of 1 indicates that the drive reads from the disk. An FUA bit of 0 indicates that data may come from the cache memory. A relative address bit of one indicates that logical block address specified is a two's complement offset from the last logical block address accessed. A value of 0 indicates that the logical block address is an absolute address. The Transfer Length field specifies the number of contiguous logical blocks of data to be transferred. A value of 0 indicates that no blocks will be transferred and is not considered an error. A Physical Block Address bit of 1 indicates that physical block addressing is used. A PBA bit of 0 indicates that logical block addressing is used. For Write-Once optical disks, blank checking is performed following a failed read. If the sector is blank, the sense key/additional sense code will be set to BLANK CHECK/Blank Sector Detected. Chapter 2 2-129