Hitachi CinemaStar P7K500 Specifications page 110

This command can change the Segment Initialized Flag. If the command writes all the user addressable
sectors and completes without encountering an error or being aborted, then the "Segment Initialized Flag"
(bit 0 of the Status Flags in the SCT Status. See0) shall be set to 1. A write to any user addressable sector
on the drive (except another complete write all), shall cause the Segment Initialized Flag to be cleared.
Reallocations as a result of reading data (foreground or background) do not clear the Segment Initialized
Flag.
HITACHI Deskstar & CinemaStar P7K500 Hard Disk Drive specification (Rev 1.1)
102