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Shingled magnetic recording disk drive with compensation for the effect of far track erasure (FTE) on adjacent data bands

a technology of magnetic recording and compensation, applied in the field of magnetic recording hard disk drives, can solve the problems of wide-area track erasure (water) or far track encroachment or erasure (fte), and the effect of fte on adjacent data bands may be more pronounced on one side of the track

Active Publication Date: 2013-12-05
WESTERN DIGITAL TECH INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This approach effectively eliminates FTE effects in boundary regions without continuous data rewriting, enhancing data reliability and reducing bit error rates by proactively managing and invalidating affected tracks.

Problems solved by technology

A problem in both conventional HDDs and SMR HDDs is wide-area track erasure (WATER) or far track encroachment or erasure (FTE).
Tracks on one side may encounter more pronounced FTE effects due to the write head shield design or due to read-write head skew.

Method used

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  • Shingled magnetic recording disk drive with compensation for the effect of far track erasure (FTE) on adjacent data bands
  • Shingled magnetic recording disk drive with compensation for the effect of far track erasure (FTE) on adjacent data bands
  • Shingled magnetic recording disk drive with compensation for the effect of far track erasure (FTE) on adjacent data bands

Examples

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Embodiment Construction

[0017]FIG. 1 is a top view of a disk drive 100 with shingled recording according to the invention. The disk drive has a housing or base 101 that supports an actuator 130 and a spindle motor (not shown) for rotating the magnetic recording disk 10 about its center 13 in the direction indicated by arrow 15. The actuator 130 may be a voice coil motor (VCM) rotary actuator that has a rigid arm 134 and rotates about pivot 132. A head-suspension assembly includes a suspension 121 that has one end attached to the end of actuator arm 134, a flexure 123 attached to the other end of suspension 121, and a head carrier, such as an air-bearing slider 122, attached to the flexure 123. The suspension 121 permits the slider 122 to be maintained very close to the surface of disk 10 and the flexure 123 enables the slider 122 to “pitch” and “roll” on an air-bearing generated by the rotating disk 10. The slider 122 supports the read / write or recording head 109 located on the end face 112 of slider 122. ...

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Abstract

A shingled magnetic recording (SMR) disk drive has concentric shingled data tracks having data sectors with physical block addresses (PBAs), with the tracks being arranged in annular bands separated by annular inter-band gaps. The disk drive also has an on-disk extended cache region and may have writable inter-band cache (IBC) tracks in the inter-band gaps. A count is maintained in memory for each band and each IBC, and the count is incremented for each writing to a band or an IBC. When a count for a band or IBC reaches a predetermined threshold, the data is read from the tracks in the boundary region of the adjacent band that are within the range of the FTE and that data is then written to the extended cache. The FTE-affected tracks are then invalidated, meaning that PBAs can no longer be assigned to the data sectors in those tracks.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates generally to magnetic recording hard disk drives (HDDs), and more particularly to a shingled magnetic recording (SMR) HDD that compensates for the effect of far track erasure (FTE) on data tracks in the boundary regions of data bands.[0003]2. Description of the Related Art[0004]Magnetic recording disk drives that use “shingle writing”, also called “shingled recording” or “shingled magnetic recording” (SMR), have been proposed, for example as described in U.S. Pat. No. 6,185,063 B1 and U.S. Pat. No. 6,967,810 B2. In SMR, the write head, which is wider than the read head in the cross-track direction, writes magnetic transitions by making a plurality of consecutive circular paths that partially overlap. The non-overlapped portions of adjacent paths form the shingled data tracks, which are thus narrower than the width of the write head. The data is read back by the narrower read head. The narrower shi...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G11B21/02
CPCG11B5/09G11B19/045
Inventor BANDIC, ZVONIMIR Z.LE MOAL, DAMIEN CYRIL DANIELTHORSTENSON, SHAD HENRY
Owner WESTERN DIGITAL TECH INC
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