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Disk Media Management
6 - 6
C141-E167
6.3 Data Block Verification Methods (Recommended)
The recommended procedure for verifying from the INIT the normalcy of logical data blocks located
on the disk media is as shown below. It is desirable for the INIT to verify the data blocks after
initialization of the disk media is completed or when executing alternate block allocation processing
by the REASSIGN BLOCKS command.
Note:
The INIT must not recognize the defective data blocks included in the P List as normal data
blocks in the verification operation.
After the INIT has written a specific data pattern for logical data blocks which is the object of
verification using the procedure described below, it next reads those data or verifies the data blocks
by executing Verify.
(1) Setting parameters by the MODE SELECT command
Issue the MODE SELECT or the MODE SELECT EXTENDED command and prohibit retry
processing, data correction and operation of the Read-Ahead Cache feature. The necessary
parameter settings are as shown below.
a. Read/Write Error Recovery Parameters (Page 1)
• AWRE = 0, ARRE = 0
• TB = 0 or 1
• EER = 0, PER = 1, DTE = 1, and DCR = 1
• Number of Retries during Read = Zero
• Number of Retries during Write = Zero
b. Verify Error Recovery Parameters (Page 1)
• EER = 0, PER = 1, DTE = 1, and DCR = 1
• Number of Retries during Verify = Zero
c. Caching Parameters (Page 8)
• RCD = 1
(2) Writing a data pattern
Write a data pattern for verification in the data block which is the object. The recommended data
pattern at this time is X '0123456789ABCDEF' repeated. The WRITE, WRITE EXTENDED or
WRITE SAME command can be used to write data.