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When transfer of this page is requested by the MODE SENSE or
MODE SENSE EXTENDED command, the IDD reports X '16' as
the page length. However, in the MODE SELECT and MODE
SELECT EXTENDED commands, if either X '16,' X '12' or X '0A'
is specified, it is treated as if the IDD has specified the correct
page length. The X '12' and X '0A' page lengths have been
included in consideration of compatibility with previous models,
but it is recommended that the INIT use the X '16' page length to
support expanded specifications in the future.
a. Cylinder count
This parameter specifies the total number of cylinders configured in the user space on the
disk media. This value includes the number of cylinders for alternate blocks specified in
the "Alternate Track Count/Drive" parameter of the format parameters (Page code = 3), so
caution should be used. This parameter can be changed, but the INIT must specify zero or
a value less than the maximum cylinder count that can be used as "User Space."
If zero is specified in this field, it is equivalent to specifying the either the maximum
number of cylinders in the "User Space" or the number of cylinders necessary for ranking
the specified number of logical data blocks specified in the "Data block count" parameter
in the block descriptor, whichever is smaller. Furthermore, if the specification of the "Data
block count" parameter in the block descriptor is also zero, the maximum number of
cylinder is set in this field.
On the other hand, if a value other than zero is specified in this field, the IDD processes
this parameter as shown below.
•
When this page descriptor is specified together with a block descriptor in which a
value other than zero is specified in the "Data block count" parameter in the same
MODE SELECT or MODE SELECT EXTENDED command, and the value of this
parameter field does not match the value specified in the "Data block count"
parameter in the block descriptor, the IDD performs rounding processing of the
parameter with a range where it won't exceed the maximum number of cylinders, and
sets the number of cylinders in this parameter that is necessary for ranking the
specified number of logical data blocks in the "Data block count" parameter of the
block descriptor (this rounding processing is not reported).
•
When this page descriptor is specified together with a block descriptor in which zero
is specified in the "Data block count" parameter, or when it is not specified together
with the block descriptor, the number of rankable logical data blocks is determined by
the value specified in this parameter field and the value specified in the Format
parameter (Page code = 3). Furthermore, when a value which exceeds the maximum
cylinder count is specified in this parameter field, the IDD sets the maximum cylinder
count in this parameter by rounding (down) processing of this parameter. Also, if the
value specified in this parameter field less than or equal to the alternate cylinder count
specified in the "Alternate track count/drive" parameter in the Format parameters
(Page code = 3), the IDD sets the (alternate cylinder count +1) in this parameter by
rounding (up) processing. When the above rounding processing is performed, a
CHECK CONDITION status (RECOVERED ERROR [= 1] / Rounded Parameter [37-
IMPORTANT
C141-E054-02EN
4 - 39
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