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6.2.2
Re-initialization
The INIT can reinitialize the disk drive after it has been operated using the FORMAT UNIT
command.
Note:
If it is necessary after reinitialization to restore the data that were stored on the disk media, it is
necessary to save the data before executing reinitialization, then execute data restore using
system software after reinitialization.
The INIT can change the size of the spare sector area and its location as well as the number of
logical data blocks before reinitialization. The recommended procedure for reinitialization is shown
below.
However, in cases where the logical data block length is changed, the initialization
procedure described in Section 6.2.1 must be followed during installation.
(1)
MODE SELECT command
If the logical data block count (size of the User Space) or the size of the spare sector area and its
location are changed, issue the MODE SELECT EXTENDED command and specify the disk media
format attributes. The parameter specification method is the same as in the case of initialization
processing during installation, described in Section 6.2.1. If the same format attributes as at present
will continue to be used, it is not necessary to issue the MODE SELECT EXTENDED command.
(2)
FORMAT UNIT command
Issue the FORMAT UNIT command in either of the following two formats and initialize the entire
disk media surface.
a) Specify "1" in the "FmtData" bit, "0" in the "CmpLst" bit and "000" in the "Defect List Format"
field. Also, prepare only a 4-byte header, specify "0" in the "FOV," "DPRY," "DCRT" and
"STPF" bits and zero in the "Defect List Length" field.
In this FORMAT UNIT command, the entire disk media surface is initialized using the P
List and the previously existing G List, then after initialization, the data blocks are verified.
If any defective blocks are detected in the Verify operation, alternate blocks are allocated
for those data blocks. Also, the previously existing G List is saved, and the defect position
information for the defective data blocks detected in the Verify operation is added to the G
List. During initialization, alternate blocks for which sector slip processing was applied for
previously known defects are reallocated, so optimization of the logical data block locations
on the disk media can be expected.
b) Specify "0" in the "FmtData" bit and in the "CmpLst" bit and "000" in the "Defect List Format"
field. In this case, specification of the format parameters is not necessary.
In this FORMAT UNIT command, the disk media is initialized using only the P List, then
after initialization, the data blocks are verified. If any defective blocks are detected in the
Verify operation, alternate blocks are allocated for those data blocks. Also, the previously
existing G List is erased and defect position information for the defective data blocks
detected in the Verify operation is recorded in a new G List.
C141-E167
6.2 Disk Media Initialization
6 - 5
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