Read Element Status - X'B8'

Table 1 shows the format of the Read Element Status command for the 3584 Tape Library.

Table 1. Read Element Status Command
Byte Bit 7

MSB

 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

LSB
0 Operation code (X'B8')
1 LUN (Obsolete) VolTag Element Type Code
2 Starting Element Address
3
4 Number of Elements
5
6 Reserved CURDATA DVCID
7 Allocation Length
8
9
10 Reserved
11 Vendor Specific (B'00') Reserved (B'0000') Flag (B'0') Link (B'0')

The following 3584 Tape Library-specific parameters apply:

  • VolTag (Volume Tags): The following values apply:
      B'0' Requests the device to not report volume tag information.
      B'1' Requests the device to report volume tag information.
  • Element Type Code: The following values apply:
      X'0' Reports all element types.
      X'1' Reports Medium Transport Elements only.
      X'2' Reports Storage Elements only.
      X'3' Reports Import/Export Elements only.
      X'4' Reports Data Transfer Elements only.
  • Starting Element Address: The minimum element address to report.
  • Number of Elements: The maximum number of elements to be included in this report. For Element Type Code X'2', when the DVCID bit is set to B'1' and the VolTag bit is set to B'1', the maximum number of elements that can be requested is 5,376 (X'1500'). Any request over this amount returns Illegal Request with the ASC/ASCQ set to 24/00 (Invalid Field in CDB).
  • DVCID (Device ID): The following values apply:
      B'0' Requests the library to report status for the element indicated in the Element Type Code field.
      B'1' Requests the library to report device identifiers, if available, for the following elements:
    • Data Transfer Elements: If this bit is set to 1b, the VolTag field must be set to 0b and the Element Type Code field must be set to 4h. Only the device identifier data is valid in the response. All other data is returned as invalid with an ASC/ASCQ in each element descriptor set to 81/00 or 82/00 (Status is Questionable).
    • Storage Elements: If this bit is set to 1b, all element descriptor data for the element is returned the same as when the bit is set to 0b. Additionally, device identifier data is returned that contains the physical location of the cartridge.
      Note: Cartridge physical location reporting is not supported if the control path drive is an LTO Ultrium 1 or LTO Ultrium 2 drive.
  • CURDATA: The following values apply:
      B'0' Motion is allowed as needed to return a maximum set of valid element status data.
      B'1' Motion is not allowed; a minimum set of valid data might be returned. This field is supported for SCSI-3 compliance, but it is not required to be set to B'1' to obtain the Device IDs for the Data Transfer Elements.
  • Allocation Length: The maximum number of bytes of data to be returned for this report.