Shingled Magnetic Recording with Operational Based Track Spacing

Patent metadata

Field	Value
Publication number	US-2018182432-A1
Application number	US-201615388042-A
Country	US
Kind code	A1
Filing date	Dec 22, 2016
Priority date	Dec 22, 2016
Publication date	Jun 28, 2018
Grant date	—

Abstract

A data storage device can employ shingled magnetic recording with data tracks oriented in order to optimize operational parameters, such as bit error rate. A data storage device can consist of a plurality of data tracks overlapping in a band on a data storage medium. First, second, and third data tracks of the band can be respectively separated by a uniform first track pitch during testing the band for an operational parameter. The first track pitch may then be adjusted to provide at least two different adjusted track pitches with each track pitch measured between longitudinal centerlines of adjacent data tracks of the band.

First claim

1 . An apparatus comprising a data storage medium with first, second, and third data tracks arranged in a single band to overlap to provide shingled magnetic recording, the first and second data tracks oriented with a first track pitch, the second and third data track oriented with a second track pitch, each track pitch measured from a longitudinal centerline of the respective data tracks, the first and second track pitches being different, selected in response to a tested parameter of the data storage medium, and adjusted to fit a curve to reduce track-to-track measurement variations within the first band.

2 . The apparatus of claim 1 , wherein the tested parameter is bit error rate.

3 . The method of claim 10 , wherein a second band of the data storage medium has multiple data tracks oriented with third and fourth track pitches each selected in response to the tested bit error rate.

4 . The method of claim 10 , wherein the longitudinal centerline of each data track matches a write centerline.

5 . The method of claim 10 , wherein the first track pitch is larger than the second track pitch, the first track pitch located proximal an edge of the first band.

6 . The method of claim 5 , wherein the second track pitch is positioned approximately at a center of the first band.

7 . The method of claim 10 , wherein the first track pitch is smaller than the second track pitch, the first track pitch located proximal an edge of the first band, the second track pitch located distal the edge of the first band.

8 . The method of claim 10 , wherein the first band comprises at least three different track pitches.

9 . The method of claim 8 , wherein the at least three different track pitches gradually decrease from a first edge of the first band to a centerline of the first band.

10 . A method comprising:
arranging a plurality of data tracks in a first band on a data storage medium to overlap and provide shingled magnetic recording, first, second, and third data tracks of the first band respectively separated by a uniform first track pitch; testing the first band for bit error rate; adjusting the first track pitch to provide at least two different adjusted track pitches to decrease the bit error rate of at least one of the plurality of data tracks, each track pitch measured between longitudinal centerlines of adjacent data tracks of the first band; and altering the at least two different adjusted track pitches to at least two different final adjusted track pitches to fit each adjusted track pitch to a curve, the at least two different final adjusted track pitches having reduced track-to-track measurement variations within the first band compared to the at least two different adjusted track pitches.

11 . The method of claim 10 , wherein the first track pitch is adjusted to provide different second, third, and fourth track pitches.

12 . The method of claim 11 , wherein the second track pitch is larger than the first track pitch and the third track pitch is smaller than the first track pitch.

13 . The method of claim 11 , wherein the fourth track pitch is smaller than the first, second, or third track pitch, the fourth track pitch positioned in a center of the first band.

14 . The method of claim 10 , wherein the at least two different track pitches are fit to a parabolic curve.

15 . The method of claim 10 , wherein a second band on the data storage medium initially has a plurality of data tracks respectively separated by the uniform first track pitch that are adjusted into at least three different adjusted track pitches to lower the bit error rate of at least two data tracks of the second band.

16 . The method of claim 15 , wherein the adjusted track pitches of the first band are different than the adjusted track pitches of the second band.

17 . The method of claim 10 , wherein the bit error rate of at least one data track of the first band increase and the bit error rate of at least two data tracks of the first band decrease as a result of the adjusting step.

18 . A method comprising:
arranging a plurality of data tracks in a first band on a data storage medium to overlap and provide shingled magnetic recording, first, second, and third data tracks of the first band respectively separated by a uniform first track pitch as defined by servo data stored on the data storage medium; testing the first band for bit error rate; adjusting the first track pitch to provide at least two different adjusted track pitches to decrease the bit error rate of at least one of the plurality of data tracks, each track pitch measured between longitudinal centerlines of adjacent data tracks of the first band; and altering the at least two different adjusted track pitches to at least two different final adjusted track pitches to fit each adjusted track pitch to a standard deviation curve, the at least two different final adjusted track pitches having reduced track-to-track measurement variations within the first band compared to the at least two different adjusted track pitches.

19 . The method of claim 18 , wherein the first track pitch is adjusted by assigning an offset value to the servo data for the respective data tracks of the first band.

20 . The method of claim 18 , wherein a second band of data tracks on the data storage medium is adjusted from the first track pitch to provide at least three adjusted different track pitches, the adjusted track pitches of the first band being different than the adjusted track pitches of the second band.

Assignees

• Seagate Technology Llc

Inventors

• Liu Xiong
• Li Quan
• Yang Kai

Classifications

• G11B5/59688

  Servo signal format patterns or signal processing thereof, e.g. dual, tri, quad, burst signal patterns · CPC title

• G11B5/59633

  Servo formatting (G11B5/59627, G11B5/59677, G11B5/59683, G11B5/59688 take precedence) · CPC title

• G11B5/596

  for track following on disks {(G11B5/5526, G11B5/5552, G11B5/5565, G11B5/5582 take precedence)} · CPC title

• G11B20/1816

  Testing · CPC title

• G11B2020/1238

  track, i.e. the entire a spirally or concentrically arranged path on which the recording marks are located · CPC title