Format of Twelve-Byte SCSI Command Descriptor Block (CDB): Offset Size Description ) 00h BYTE operation code (see #03239) 01h BYTE logical unit number (bits 7-5), SCSI-1/SCSI-2 reserved in SCSI-3 02h DWORD logical block address (low word) 06h DWORD transfer length 0Ah BYTE reserved 0Bh BYTE control byte SeeAlso: #03236,#03237