Fujitsu MBC2036RC, MBC2073RC, MBA3300RC, MBA3147RC, MBA3073RC Sense data basic information

6.1 Sense Data

6.1.2 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 HDD 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 HDD, 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 4.4.5 and 4.4.6).

(4) Sense key

This field shows the cause of the sense data being generated. More details reasons are indicated in the additional sense code field (Byte 12) and the additional sense code qualifier field (Byte 13). Table 6.3 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 HDD, only the READ LONG command and the WRITE LONG command display this information. For details, see the descriptions of these commands (Sections 4.4.5 and 4.4.6).

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