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This function is applied once only during execution of one command. Alternate block
allocation processing and copying are executed for the first defective data block to be detected
during execution of a command, but if a second defective data block is detected, the command
that is being executed at that point is terminated with an error. However, by the INIT's
reissuing the same command, auto alternate block allocation is applied sequentially and error
recovery can be attempted.
Remark:
1.
When this function is specified (ARRE = "1"), the EER flag's specification in the
MODE SELECT parameter is made invalid and Read retry processing is performed
up to the number of times specified in the "Number of Retries during Read"
parameter. If "0" is specified in the DCR flag, correction processing of the data is
performed afterward (see Section 5.3.1 (3)). When "1" is specified in the DCR flag,
ECC correction processing is prohibited, so even if "1" is specified in the ARRE flag,
auto alternate block allocation processing will not be executed for errors in the data
area.
2.
When errors in the data area are recovered from by ECC correction processing, before
implementing alternate block allocation processing, rewriting of the recovered data
and a verify check (rereading) are performed. If data are recovered by rewriting,
alternate block allocation of that data block is not performed.
3.
When a write operation is prohibited through the setting terminal, the auto alternate
block allocation processing specification is disabled.
5.3.3
Error recovery processing control
The INIT can, by specifying the MODE SELECT parameters, can control the error recovery
processing (retries) of the IDD with respect to each type of error related to the disk drive.
Table 5.5 shows the types of error and the method of specifying the number of retries for
those errors. for those items where the INIT can specify the number of retries, normally, it is
recommended that the default value or a greater number of times be specified. If a value
smaller than the default value is specified, and commands are terminated abnormally without
error recovery processing succeeding, the INIT should reset the corresponding MODE
SELECT parameters at the default value, then reexecute the original commands.
The MODE SELECT parameters related to disk drive error recovery processing which the
INIT can specify are shown below. See the description of the MODE SELECT command
(Section 3.1.5) concerning details of the functions of each parameter. The INIT can issue the
MODE SELECT or MODE SELECT EXTENDED command as necessary and select the error
recovery flags and the number of retries.
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C141-E054-02EN
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