Element Type 4: Data Transfer (DVCID=B'0')

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This element descriptor block is used to report the status of the drive.

Table 1. Element Type 4: Data Transfer Element Descriptor (DVCID=B'0')
Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0-1 Element Address
2 Reserved Access Except Reserved Full
3 Reserved
4-5 ASC/ASCQ
6 Not Bus Reserved ID Valid LU Valid Reserved Logical Unit Number (B'000')
7 SCSI Bus Address
8 Reserved
9 SValid Invert (B'0') Reserved
10-11 Source Storage Element Address
12-47 Primary Volume Tag Information
48-51
or
12-15		 Reserved
  • Element Address: The range of element addresses that are reported in this field depend on the library's configuration.
    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:
      B'0' Indicates that access to the Data Transfer element by a Medium Transport Element is denied.
      B'1' Indicates that access to the Data Transfer element by a Medium Transport Element is allowed.
    Note: Examples of when access would be denied include (1) when the tape drive contains a cartridge in the loaded position and (2) when a shared tape drive contains a cartridge that is assigned to another logical library.
  • Except: The following values apply:
      B'0' The element is in a normal state.
      B'1' The element is in an abnormal state.
  • Full: The following values apply:
      B'0' The element does not contain a cartridge.
      B'1' The element contains a cartridge in a loaded or ejected position.
    Note: A cartridge in the loaded position is indicated by the Full bit set to B'1' and the Access bit set to B'0'. A cartridge in the ejected position is indicated by the Full bit set to B'1' and the Access bit set to 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:
      11/00 Unable to Read Bar Code Label
      81/00 Status is Questionable (for example, the door is open)
      82/00 Drive is Not Present or is Unable to Communicate
      83/00 Medium in Drive (Unable to Access Bar Code Label)
  • Not Bus: Not this bus. This bit is not supported.
  • ID Valid: The following values apply:
      B'0' Indicates that the SCSI Bus Address field is not valid.
      B'1' Indicates that the SCSI Bus Address field contains valid information.
  • LU Valid: The following values apply:
      B'0' Indicates that the Logical Unit Number field is not valid.
      B'1' Indicates that the Logical Unit Number field contains valid information.
  • Logical Unit Number: The LUN is always 0.
  • SCSI Bus Address: Set to the SCSI ID of the drive.
  • SValid:
      B'0' Indicates that the Source Storage Element Address field provides vendor-specific information. The SValid field is set to B'0' when the Full field is set to B'0'.
      B'1' Indicates that the Source Storage Element Address field is valid.
  • Invert: The tape library does not invert cartridges.
  • Source Storage Element Address: When SValid is B'1', this field provides the address of the last storage element from which this cartridge was moved. When SValid is B'0' and the Full field is set to B'0', this field provides the following vendor-specific information:
      Bit Description
      15–1 Reserved
      0 B'0' Element is located in the preferred zone of accessor A or is not currently assigned to a physical location.
        B'1' Element is located in the preferred zone of accessor B.
  • Primary Volume Tag Information: The presence or absence of this field is indicated by the PVolTag field in byte 1 of the Element Status Page. To view the content of this page, go to the section about Element Status Page. This is a 36 byte ASCII field that contains the cartridge bar code label, left-adjusted and padded on the right with blanks.
  • Reserved: Bytes 48-51 (bytes 12-15 if PVolTag is set to B'0').