Operating instructions

15-6
SCSI REFERENCE 1012975
CHAPTER 15—READ ELEMENT STATUS (B8h)
 If the descriptor being returned is for a data transfer element (a tape drive),
the element descriptor length changes depending on the setting of the
DVCID, VolTag, and S/N Req bits, as shown in Table 15-1.
Byte Count of Descriptor Data Available – Bytes 05 through 07
This field indicates the total number of bytes of element descriptor data
available for the elements of this element type that meet the CDB
requirements. This value is the Element Descriptor Length multiplied by the
number of element descriptors. This value is not adjusted to match the value
that you specified in the Allocation Length field of the CDB.
15.3.3 ELEMENT DESCRIPTORS
The following sections contain the field definitions for the three types of
element descriptors for the autoloader:
 Medium transport element: The cartridge loader
 Storage elements: The cartridge cells
 Data transfer element: The tape drive
Each element descriptor includes the element address and status flags. Each
element descriptor can also contain sense code information as well as other
information, depending on the element type.
Notes:
 The element descriptors for the elements are very similar, with the exception of
a few of the fields. Note the differences in bytes 02, 06, and 07 for the element
descriptors.
 The autoloader does not support alternate volume tags. This information is not
included in any of the element descriptors.
Table 15-1 Element descriptor length for the data transfer element
DVCID VolTag S/N Req Element Descriptor Length (bytes)
000 24
001 34
010 60
011 70
100 58
101 68
110 94
111 104