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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)
When desiring to clearly specify the number of cylinders in the "User Space," specify that
value in the "Cylinder count" field. In this case, it is necessary to note that the number of
cylinders in the User Space includes the number of alternate cylinders specified in the
Format parameters (Page 3). When it is not particularly necessary to specify the number of
cylinders, zero, or a value equal to the default value, may be specified in the "Cylinder
count" field. In this case, the number of cylinders necessary to secure the number of
logical data blocks specified in the "Data block count" field in the block descriptor, or the
maximum number of cylinders that can be used as User Space on the disk drive,
whichever is smaller, will be allocated to user space. Furthermore, if zero is specified in
both the "Cylinder count" field and the "Data block count" field in the block descriptor,
the maximum number of cylinders on the disk drive that can be used as User Space will be
allocated to User Space.
6 - 4
C141-E054-02EN
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