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Command Specifications
"Support" Bit
2
0
0
0
0
1
1
1
1
c.
d.
(7) VPD information
144
Table 4.6 Support
1
0
0
0
Data about the requested SCSI operation code is not
currently available.
0
1
The device server does not support the tested SCSI
operation code. All data after byte 1 is undefined.
1
0
Reserved
1
1
The device server supports the tested SCSI operation code
in conformance with an SCSI standard.
0
0
Vendor-specific (undefined)
0
1
The device server supports the tested SCSI operation code
in a vendor-specific manner.
1
0
Vendor-specific (undefined)
1
1
Reserved
If the "Support" field contains "000b", all data after byte 1 is not valid.
One possible reason for "support" being "000b" is the device server's
inability to retrieve information stored on the media. When this is the
case, a subsequent request for command support data may be successful.
CDB size
This field contains the number of bytes in the CDB for the operation code
being queried, and the size of the "CDB Usage Data" field in the return data.
CDB usage data
This field contains information about the CDB for the operation code
being queried. The first byte of the "CDB usage data" contains the
operation code for the operation being queried. All bytes except the first
byte of the "CDB usage data" contains a usage map for bits in the CDB
for the operation code being queried.
The bits in the "Usage map" have a one-for-one correspondence to the
CDB for the operation code being queried. If the device server evaluates
a bit as all or part of a field in the CDB for the operation code being
queried, the usage map contains a one in the corresponding bit position.
If the device server ignores or treats as reserved a bit in the CDB for the
operation code being queried, the usage map contains a zero in the
corresponding bit position. The usage map bits for a given CDB field all
have the same value.
Thus, the CDB usage bit map for this command for a device server that
implements command support data but not vital product data is: 12h, 02h,
FFh, 00h, FFh, 00h.
Description
C141-C013
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