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US 8,427,772 B2Granted
Patterned-media magnetic recording disk drive with data island misplacement information in the servo sectors
AssigneeHGST Netherlands B.V.
InventorsJeffey S. Lille, Ricardo Ruiz
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Abstract
A disk drive with patterned-media disks has information recorded in the servo sectors that identifies misplacement of the data islands in the data regions between the servo sectors. This misplacement information is read from the servo sectors prior to writing to correct either or both the radial position of the write head and the timing of the write pulses to the data islands. The misplacement information may include radial deviation of the data tracks, circumferential or along-the-track misplacement of the data islands, or the location of defective data islands.
Claims17
A magnetic recording disk drive comprising:
- a rotatable magnetic recording disk having a plurality of generally circular data tracks, a plurality of angularly spaced synchronization marks extending generally radially across the data tracks, and a plurality of angularly spaced servo sectors extending generally radially across the data tracks, the data tracks being patterned into discrete circumferentially spaced magnetizable data islands, the data islands being grouped into data regions located between the servo sectors, each data region being grouped into a plurality of data sectors, and wherein the servo sectors contain positioning information and data island misplacement information for the data islands;
- a controller for selecting the data tracks and data sectors where data is to be written;
- a write head for writing data to the data sectors by generating write pulses to magnetize the data islands in the data sectors;
- a write clock coupled to the write head for controlling the write pulses to the data islands;
- a read head for sensing the synchronization marks and reading the positioning information and data island misplacement information in the servo sectors;
- an actuator coupled to the read head and write head for moving the write head to the data tracks and maintaining the write head on the data tracks in response to positioning information read by the read head;
- synchronization mark detection circuitry coupled to the read head for controlling the write clock;
- and
- write clock adjustment circuitry responsive to the data island misplacement information read by the read head for adjusting the timing of the write clock pulses to the data islands.
6 more elements
A magnetic recording disk drive comprising:
- a rotatable magnetic recording disk having a plurality of generally circular data tracks, a plurality of angularly spaced synchronization marks extending generally radially across the data tracks, and a plurality of angularly spaced servo sectors extending generally radially across the data tracks, the data tracks being patterned into discrete circumferentially spaced magnetizable data islands, the data islands being grouped into data regions located between the servo sectors, each data region being grouped into a plurality of data sectors, and wherein the servo sectors contain positioning information and data island circumferential misplacement information for the data islands;
- a controller for selecting the data tracks and data sectors where data is to be written;
- a write head for writing data to the data sectors by generating write pulses to magnetize the data islands in the data sectors;
- a write clock having adjustable phases and coupled to the write head for controlling the write pulses to the data islands;
- a read head for sensing the synchronization marks and reading the positioning information and data island circumferential misplacement information in the servo sectors;
- wherein the read head and write head are circumferentially offset from each other, each data track having an associated head circumferential offset (HCO) value;
- an actuator coupled to the read head and write head for moving the write head to the data tracks and maintaining the write head on the data tracks in response to positioning information read by the read head;
- synchronization mark detection circuitry coupled to the read head for controlling the write clock;
- and
- phase adjustment circuitry for adjusting the phase of the write clock by the HCO value associated with said selected data track to be written and by a phase adjustment amount (p0) corresponding to said circumferential misplacement information read by the read head.
7 more elements
Dependencies are inferred from the claim text.