Hitachi T7K250 - Deskstar - Hard Drive Specifications page 28

Physical cylinder is calculated from the starting data track of 0. It is not relevant to logical
CHS. Depending on the capacity some of the inner zone cylinders are not allocated.
Data cylinder
This cylinder contains the user data which can be sent and retrieved via read/write commands and a spare area for
reassigned data.
Spare cylinder
The spare cylinder is used by Hitachi Global Storage Technologies manufacturing and includes data sent from a
defect location.
Deskstar T7K250 Hard Disk Drive Specification
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