Element Type 4: Data Transfer (DVCID=B'1')

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This element descriptor block is used to report the device identifiers for the drive.

Table 1. Element Type 4: Data Transfer Element Descriptor (DVCID=B'1')
Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0-1 Element Address
2 Reserved Access (B'0') Except (B'1') Reserved Full (B'0')
3 Reserved
4-5 ASC/ASCQ
6 Not Bus (B'0') Reserved ID Valid (B'0') LU Valid (B'0') Reserved Logical Unit Number (B'000')
7 SCSI Bus Address (X'00')
8 Reserved
9 SValid Invert (B'0') Reserved
10-11 Source Storage Element Address
12-49
or
12-51		 Identification Descriptor
  • Element Address: The range of element addresses that are reported in this field depend on the library's configuration. For more information, see SCSI element addresses. The range is X'0101–0148'.
    Note: A valid configuration might include a 'gap' in the drive positions (for example, drives might be installed in positions 1 and 3 but not position 2). The Data Transfer Element information reported in Mode Sense and Read Element Status data always includes these 'gaps' (in the preceding example, the range of Data Transfer Element addresses includes X'0101' , X'0102', and X'0103'). The ASC/ASCQ field of the Data Transfer Element Descriptor indicates whether the associated drive is not present.
  • Access: Not supported when DVCID = B'1'.
  • Except: Always set when DVCID = B'1'.
  • Full: Not supported when DVCID = B'1'.
  • ASC/ASCQ: More Sense Code/Additional Sense Code Qualifier. The ASC/ASCQ: field might provide specific information on an abnormal element state when the Except bit is set to B'1'. The following values apply:
      8100 Status is Questionable, Drive is Present
      8200 Status is Questionable, Drive is Not Present
  • Not Bus: Not this bus.
  • ID Valid: Not supported when DVCID = B'1'.
  • LU Valid: Not supported when DVCID = B'1'.
  • Logical Unit Number: The LUN is always 0.
  • SCSI Bus Address: Not supported when DVCID = B'1'.
  • SValid:
      B'0' Indicates that the Source Storage Element Address field provides vendor-specific information.
      B'1' Not supported when DVCID = B'1'.
  • Source Storage Element Address: When SValid is B'0', this field provides the following vendor-specific information:
      Bit Description
      15–11 Drive frame physical location. Binary encoded value that represents the drive frame position (e.g., B'10001' = frame 17).
      10–8 Drive column physical location. Binary encoded value that represents the drive column number (e.g., B'100' = column 4).
      7–4 Drive row physical location. Binary encoded value that represents the drive row number (e.g., B'0011' = row 3).
      3–1 Reserved
      0 B'0' indicates the element is located in the preferred zone of accessor A or is not currently assigned to a physical location.
        B'1' indicates the element is located in the preferred zone of accessor B.
    Note: Frames and columns are numbered left to right when viewing from the front of the library. Rows are numbered top to bottom.
  • Identification Descriptor: Indicates that the following information applies:
    • If no drive is present, all bytes are set to X'00'.
    • For LTO or 3592 devices, these bytes are the same as reported by the drive in Inquiry Page X'83', specifically the Identification Descriptor with Identifier Type of X'1'.