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3.3 Format Commands
C141-E167
3 - 87
The logical block address of defective data blocks is described in 4-byte format in the defect
descriptor. When multiple defect descriptors are specified, it is best for the INIT to describe defect
descriptors in the ascending order of the logical data block addresses.
Furthermore, if the addresses of logical data blocks specified in the defect descriptor list overlap
each other, This command is terminated with a CHECK CONDITION status (ILLEGAL REQUEST
[=5] / Invalid field in parameter list [=26-00] and none of the alternate block allocation processing in
that command is executed.
The IDD allocates alternate blocks to the specified data blocks in order from the top of the defect
descriptor list. When all the usable spare sectors have been used up, and it is impossible to allocate
alternate blocks, execution of this command is terminated at that point and a CHECK CONDITION
status is reported. The sense data at this time indicate the following contents.
• Sense key: 4 = HARDWARE ERROR
• Sense code/Sub-sense code: 32-00 = No defect spare location available
• “VALID” bit: “1”
• Information field Logical block address specified in the defect descriptor
at the point when alternate block allocation becomes
impossible.
• Command inherent information field
Also, when this command is terminated abnormally with a CHECK CONDITION status due to any
one of several other types of error besides the above error, the logical block address specified in the
first defect descriptor which did not undergo alternate block allocation is reported in the “Command
inherent information” field in the sense data. However, if alternate block allocation processing of
the defect descriptors for which alternate block allocation has not been implemented cannot be
specified, or if alternate block allocation of all the specified defect descriptors has been completed,
the “Command inherent information” field indicates X ‘FFFFFFFF.’
When alternate block allocation processing is successful, the defect position information on the disk
media related to the data blocks specified in the defect descriptor list is recorded on the disk media as
the defect list (G List). The INIT can read the contents of the G List using the READ DEFECT
DATA command. Also, this command has no influence on the contents of the primary defect list (P
List).
Note:
The defect position information in the G List is physical block addresses (logical data block
addresses are allocated when no defect exists on the disk media). Therefore, the values specified
in this command’s defect descriptor list (logical block addresses) may not necessarily be the
same as the contents of the G List read by the READ DEFECT DATA command after this
command is terminated. For details, see the description of the READ DEFECT DATA
command (Section 3.3.3).
Note: Precautions for use of command
If this command is terminated with a CHECK CONDITION status, the sense code/sub-sense code in
the sense data is other than “No defect spare location available [=32-00], and a valid logical block
address (other than X ‘FFFFFFFF’) is displayed in the “Command inherent information” field, it is
necessary for the INIT to reissue this command by the following procedure after executing recovery
processing (shown in Section 5.2) in accordance with the contents of the sense data.