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Disk Media Management
6.2 Disk Media Initialization
6.2.1 Initialization during installation
The disk drive is initialized for the inherent (default) data format for each
respective model name (model class) when it is shipped from the factory, so
ordinarily, it is not necessary to initialized (format) the disk media when it is
installed in a system. However, in cases where data attributes which differ from
the default format are necessary, initialization (formatting) of the entire disk
media by the following procedures is necessary. At this time, the INIT can
change the following data format attributes.
•
The logical data block length.
•
The number of logical data blocks or the number of cylinders in the User
Space.
•
The size of the spare area for alternate blocks.
(1) Issuing the MODE SELECT command
The MODE SELECT or MODE SELECT EXTENDED command is issued and
the format attributes on the disk media are specified. The necessary parameters at
this time are as follows.
a.
Block descriptor
The logical data block size (byte length) is specified in the "Data block
length" field. Also, when desiring to clearly specify the logical data block
count, specify that value in the "Data block count" field. If not, zero may be
specified in the "Data block count" field. In that case, the number of logical
data blocks after initialization will be determined by the values specified in
the Format parameters (Page 3) and the Drive parameters (Page 4).
b. Format parameters (Page 3)
Specify the number of spare sectors secured in each cylinder in the "Alternate
sector count/zone" field. It is desirable not to specify a value that is lower
than the IDD's default value in this field.
c.
Drive parameters (Page 4)
The number of cylinders in the "User Space," cannot be changed. The
number of cylinders necessary to secure the number of logical data blocks
specified in the "Data block count" field in the block descriptor will be
allocated to the user space.
6-4
C141-C012
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