Fujitsu MAA3182FC Series Manual page 304

• Alternate block allocation processing during FORMAT UNIT command
execution
With the FORMAT UNIT command, alternate block allocation is done by sector slip
processing until all the spare sectors within the same cylinder have been used up for
defective sectors included in the type of defect list (P, G or D) specified in the
command. When all the spare sectors in the same cylinder have been used up,
subsequent defective sectors in that cylinder are treated by allocating spare sectors in
an alternate cylinder by alternate sector processing.
After implementing this alternate block allocation and initializing the disk media, at
times when a data block Verify (Certification) operation is not prohibited, the IDD,
reads all the initialized data blocks and verifies their normalcy. If a defective data
block is detected during this processing, the IDD generates the C List as defect
position information and allocates alternate blocks by alternate sector processing for
those defective data blocks. In this case, if there are any unused spare sectors in the
same cylinder as the defective data blocks, alternate blocks are allocated within the
same cylinder, but if the spare sectors are all used up in the same cylinder, alternate
blocks are allocated in spare sectors in an alternate cylinder.
• Alternate block allocation processing by the REASSIGN BLOCKS command
With the REASSIGN BLOCKS command, alternate block allocation is performed by
alternate sector processing for defective logical data blocks specified by the INIT. In
this case, if there are unused spare sectors in the same cylinder as the specified
defective logical data blocks, alternate block allocation is done within the same
cylinder, but if all the spare sectors in the same cylinder have been used up, alternate
blocks are allocated in spare sectors in an alternate cylinder.
• Auto alternate block allocation processing
If auto alternate block allocation processing is permitted by the AWRE flag or the
ARRE flag of the MODE SELECT parameters, the IDD executes alternate clock
allocation automatically by alternate sector processing for defective data blocks
detected during execution of the WRITE, WRITE EXTENDED, WRITE AND
VERIFY, READ and READ EXTENDED commands. The alternate block allocation
method in this case is the same as in the case of the REASSIGN BLOCKS command.
See the description in Section 4.3.2 concerning "Auto Alternate Block Allocation
Processing".
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