Fujitsu MAA3182FC Series, Руководство пользователя

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C141-E054-02EN 5 - 3
5.1.2 Sense data basic information
Bytes 0 to 17 of the sense data are basic information which show the contents of the error that
has occurred. The INIT can know the contents of the error and the key information that is
necessary for recovery processing by analyzing this basic information. Each field and the
meanings of bits in the sense data basic information are explained below.
(1) Valid
When this bit is “1,” it indicates that the values shown in the information field (bytes 3 to 6)
are valid. On the other hand, when this bit is “0”, it indicates that the information field does
not contain valid information.
(2) Error code
This field shows the format and type of sense data. The IDD always displays X ‘70’ (current
error) or X ‘71’ (deferred error), which has the meaning “expanded sense data format” in this
field.
(3) ILI (incorrect length indicator)
When this bit is “1,” it indicates that the transfer byte length requested in the command did not
coincide with the data block length on the disk media. In the IDD, the only commands that it
reports “1” in this bit for are the READ LONG command and the WRITE LONG command.
For details, refer to the descriptions of these commands (Sections 3.4.5 and 3.4.6).
(4) Sense key
This field shows the cause of the sense data being generated. More details reasons are
indicated in the sense code field (Byte 12) and the sub-sense code field (Byte 13). Table 5.1
shows a list of the meanings of sense keys.
(5) Information
This field shows information related to the error that has been detected and is valid only when
the Valid bit is “1.” Depending on the command where the error occurred, additional
information other than the information in this field may be indicated in the command inherent
information field. The information shown in this field has the following meanings depending
on the value of the “ILI” bit.
a) When the “ILI” bit is “0,” the logical block address of the data block where the error
occurred is indicated.
b) When the “ILI” bit is “1,” the difference between the transfer byte length requested by the
command and the actual data block length on the disk media is indicated. If the difference
is a minus value, (if the request transfer byte count is smaller), it is expressed as a
complement of 2. In the IDD, only the READ LONG command and the WRITE LONG
command display this information. For details, see the descriptions of these commands
(Sections 3.4.5 and 3.4.6).