Seagate Ultra160 Product Manual page 305

SCSI Interface Product Manual, Rev. B
Additional sense codes provide further detail describing the sense key. Additional sense code qualifiers
add further detail to the additional sense code. The additional sense code and additional sense code qual-
ifier may be used by application clients where sophisticated error recovery procedures require detailed
information describing the error and exception conditions.
The Sense Key field is mandatory and indicates generic information describing an error or exception con-
dition. The sense keys are defined in Section 8.38.2.
[8] The contents of the INFORMATION field is device-type or command specific and is defined within the
appropriate standard for the device type or command of interest. Device servers shall implement the
INFORMATION field. Unless specified otherwise, this field contains:
a. the unsigned LOGICAL BLOCK ADDRESS associated with the sense key, for direct-access devices
(device type 0), write-once devices (device type 4), CD-ROM devices (device type 5), and optical
memory devices (device type 7);
b. the difference (residue) of the requested length minus the actual length in either bytes or blocks, as
deter-mined by the command, for sequential-access devices (device type 1), printer devices (device
type 2), processor devices (device type 3) and some direct access device commands, except as
defined for d) below. Negative values are indicated by two's complement notation;
c. the difference (residue) of the requested number of blocks minus the actual number of blocks copied or
compared for the current segment descriptor of a COPY, COMPARE, COPY AND VERIFY, or
Extended COPY command; or
d. for sequential-access devices operating in buffered modes 1h or 2h that detect an unrecoverable write
error when unwritten data blocks, filemarks, or setmarks remain in the buffer, the value of the informa-
tion field for all commands shall be:
• the total number of data blocks, filemarks, and setmarks in the buffer if the device is in fixed block
mode (block length field of the MODE SENSE block descriptor is non-zero and the fixed bit of the
Write command is one); or
• the number of bytes in the buffer, including filemarks and setmarks, if the device is in variable mode
(the fixed bit of the Write command is zero).
For additional information, see SSC (SCSI Stream Device Command Set, T10/997D).
[9] The ADDITIONAL SENSE LENGTH field indicates the number of additional sense bytes to follow. If the
ALLOCATION LENGTH of the command descriptor block is too small to transfer all of the additional sense
bytes, the additional sense length is not adjusted to reflect the truncation.
[10] The COMMAND-SPECIFIC INFORMATION field contains information that depends on the command that
was executed. Further meaning for this field is defined within the command description. The COMMAND-
SPECIFIC INFORMATION field is mandatory if the device server supports any of the following com-
mands: COPY, COMPARE, COPY AND VERIFY, Extended COPY and REASSIGN BLOCKS.
[11] The Additional Sense Code (ASC) indicates further information related to the error or exception condition
reported in the sense key field. Device servers shall support the ASC field. Support of the additional
sense codes not explicitly required by this manual is optional. A list of additional sense codes is in Section
8.38.3. If the device server does not have further information related to the error or exception condition,
the additional sense code is set to No Additional Sense Information.
[12] The Additional Sense Code Qualifier (ASCQ) indicates detailed information related to the additional sense
code. The additional sense code qualifier is optional. If the error or exception condition is reportable by the
device, the value returned shall be as specified in Section 8.38.3. If the device server does not have
detailed information related to the error or exception condition, the additional sense code qualifier is set to
zero.
[13] Non-zero values in the FIELF REPLACEABLE UNIT CODE field are used to define a device-specific
mechanism or unit that has failed. A value of zero in this field shall indicate that no specific mechanism or
unit has been identified to have failed or that the data is not available. The FIELD REPLACEABLE UNIT
CODE field is optional. The format of this information is not specified by this manual. Additional informa-
tion about the field replaceable unit may be available in the ASCII information page (see Section 8.6.5), if
supported by the device server.
[14] The Sense Key Specific bytes are described in Section 8.38.1.
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