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Chapter 8 SCSI Commands
8.17.2. Storage element descriptor
The Storage element descriptor is shown below.
Table 8.17.2.1 : Storage element descriptor
The Element Address area is set to the Address of an Element of the autoloader
returned by this Element Descriptor Block.
An Access bit of 1 indicates that this Element can be accessed by the picker
(Medium Transfer element). A bit of zero indicates that this Element cannot be
accessed by the picker. With this autoloader, the picker can access the Storage
element, so this is 1.
An Exception (Except) bit of 1 indicates that the Element is faulty. An
Exception bit of 0 indicates that the element is in the normal state. When the bit
is 1, the ASC/ASCQ area becomes valid to show the fault.
A Full bit of 1 indicates that there is media in the Element. A bit of 0 indicates
that there is no media in the element. This value is always 1.
The Additional Sense Code area contains information on the Element with a
fault condition. The value in this area is the same as that defined as the
Additional Sense Code shown for REQUEST SENSE data.
The Additional Sense Code Qualifier area contains information about the faulty
Element. The value in this area is the same as the Additional Sense Code
Qualifier shown for REQUEST SENSE data.
A Source Valid (Svalid) bit of 1 indicates that the Source Storage Element
Address area and Invert bit information are valid. A bit of 0 indicates that values
of this area are invalid.
An Invert bit of 1 indicates that the medium present in the element was inverted
from its orientation in the Source Storage Element with the MOVE MEDIUM
or EXCHANGE MEDIUM operation. A bit of 0 indicates that the element was
not inverted by these operations. Because the autoloader does not support this
function, it is always 0.
Bit
Byte
7
6
5
4
3
2
1
0
0
(MSB)
Element address
1
(LSB)
2
Reserved
Access Except
Reserved
Full
3
Reserved
4
Additional sense code
5
Additional sense code qualifier
6
Reserved
8
9
SValid
Invert
Reserved
10
(MSB)
Source element address
11
(LSB)
12
Primary volume tag information
(Field omitted if PVolTag = 0)
47
48
Reserved
(field moved up if Primary Volume
Tag Information field is omitted)
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