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A method to send status byte of a Write command with Post PES Check Disclosure Number: IPCOM000015629D
Original Publication Date: 2002-Mar-06
Included in the Prior Art Database: 2003-Jun-20

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Disclosed is an inplementation of Post PES (Position Error Signal) Check for HDD ··(Hard Disk Drive). Post PES Check is a method to detect Off Track Write which may result in uncorrectable read error or miscompare error. Post PES Check means that a HDD confirms the head position not only before starting a write operation but also after writing data to the media. If the HDD detects that the head position is not in the range of track following for the Write operation, it retries the write operation from the previous servo sector in which the head position was in the rangeof the track following criterion. A register is introduced for the implementation of this disclosure. It is read or written by the firmware of the HDD, and it is updated also by the HDC (Hard Disc Controller). The register keeps the LBA (Logical Block Address) until which a write operation to the media completed successfully with Post PES Check. When HDC completes its write operation to a sector, it increments the register only when the value of the register is less than the current writing LBA by the number of data sectors in a servo sector. When a Post PES Check error is detected during a write operation, HDC stops the write operation immediately. The firmware has only to refer to the register from where it has to retry the write operation. The register is used also for the automatic status transfer. The HDC has to know until where a write operation completed to send the status. It cannot send the status before Post PES Check completes. The HDC refers to the register to determine whether the status can be sent or not. When a write operation completes and the Post PES Check completes, the value of the register is updated to the end