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(3)
Correctable data read error
This error is a correctable ECC error when data are being read. Processing methods when this
error is detected differ depending on the values specified in the EER flag and DCR flag in the
MODE SELECT parameters.
If immediate correction of errors is permitted (DCR = 0, EER = 1), the IDD immediately
makes error corrections in the data buffer and sends the corrected data to the INIT. Also, in
the case of Verify processing, at the point when it judges that correction is possible, it regards
verification as being successful and continues processing of subsequent data blocks.
If error correction is permitted but immediate correction is not permitted (DCR = 0, EER = 0),
reading of data as in item (2) is retried up to the number of times specified in the other MODE
SELECT parameters ("Number of Retries during Read" or "Number of Retries during Write").
If error correction is prohibited (DCR = 1, EER = 0), reading of data as in item (2) is retried up to the
number of times specified in "Number of Retries during Read" or "Number of Retries during Write."
If the error cannot be recovered from even when this retry processing is executed, the IDD
terminates the command that is currently being executed with a CHECK CONDITION status.
The sense key in the sense data at this time is "MEDIUM ERROR [=3]" and the sense code
indicates "Unrecovered read error [=11-00]."
(4)
Other internal IDD errors
If an irrecoverable error other than those in items (1) to (3) above is detected internally in the IDD,
the IDD terminates the command that is currently being executed with a CHECK CONDITION
status. The sense key in the sense data at this time is "HARDWARE ERROR [=4]."
5.3.2
Auto alternate block allocation processing
The IDD is equipped with a function which automatically executes alternate block allocation
processing for defective data blocks detected during execution of the READ and READ
EXTENDED commands.
(1)
Auto alternate block allocation processing during a read operation
This function is enabled by specifying "1" in the ARRE flag in the MODE SELECT
parameters. Furthermore, this function is applicable to the following commands only.
• READ command
• READ EXTENDED command
When this function is permitted, if, during read processing to the data area, an error which is an
object of retry processing is detected, and which it is impossible to recover from even when reading
is retried (see Section 5.3.1 (2)) the number of times specified in the "Number of Retries during
Read" field in the MODE SELECT parameters, the IDD allocates an alternate block for that data
block and executes copying of the alternate block to the data area. Alternate block allocation
processing is the same as processing with the REASSIGN BLOCKS command. Furthermore,
recovered data copied to the alternate block are data which are read out, skipping the ID area, if there
is an ID area, or they are data which have been corrected through the ECC.
C141-E054-02EN
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