Fujitsu MBA3147RC Manuel D’Utilisation

C141-C013 

395 

If errors on the disk media which cannot be recovered from are detected, or if a 
recoverable error occurs repeatedly in the same data block, it is necessary for the 
INIT to allocate an alternate block for the data block where the error occurred 
using the REASSIGN BLOCKS command.  The procedure for alternate block 
processing is shown below. 

 

An attempt will be made to copy the contents of the data area of the 
logical data block specified in the "Defect Data" list to the alternate 
block allocated by this command, but in some cases, the data cannot 
be copied.  Confirmation of the contents of data in the allocated 
alternate block, saving of data before issuing this command and 
restoring of data after executing this command are the responsibility 
of the INIT. 
 

1)  Verify data blocks in accordance with the procedure in Section 7.3 for data 

blocks where error occurs.  When such a data block is judged to be normal, 
alternate block allocation need not be implemented.  In this case, rewrite the 
original data to that data block if necessary.  When the data block is judged to 
be defective, implement the processing in item 2) and after. 

2)  Specify a logical block address for a data block which is judged to be 

defective and issue the REASSIGN BLOCKS command. 

3)  If the REASSIGN BLOCKS command is terminated normally, verify that 

logical data block according to the procedure in Section 7.3.  If that data 
block is judged to be correct, allocate an alternate block and terminate 
processing.  When the data block is judged to be defective, return to 2) and 
issue the REASSIGN BLOCKS command again, then try reallocating another 
alternate block for that logical data block. 

The alternate block allocation history (defect position information) is registered as 
an addition to the defect list (G List).  Therefore, when reinitializing the hard disk 
with the FORMAT UNIT command (see Section 7.2.2), if use of the G List is 
specified, defect processing can be performed which reflects the operation results 
up to that time.  Also, since "Alternate sector processing" is applied in alternate 
block allocation in the REASSIGN BLOCKS command, the physical connectivity 
of the logical data block positions on the disk media is destroyed, but by 
reinitializing the disk, as long as the number of defective sectors in the cylinder 
does not exceed the number of spare sectors per cylinder, the logical data blocks 
are relocated by sector slip processing so that their physical connectivity is 
maintained.