US 9,286,926 B1 · Two-dimensional magnetic recording (TDMR) disk drive with varying servo track pitch

Abstract

A two-dimensional magnetic recording (TDMR) disk drive has a disk with servo tracks with a track pitch that varies across the radius of the disk. The servo track pitch (STP) is related to the cross-track spacing (CTS) of the multiple read sensors in the TDMR head structure. The CTS is given by the equation: CTS=(CTO)cos θ+(ATO)sin θ, where θ is the skew angle, and CTO is the cross-track spacing and ATO the along-the-track spacing of the read sensors at zero skew angle. The optimal variable STP profile results in track misregistration reduction because it allows each read sensor to read a different servo half-track and thus noise sources not correlated to noise sources read by the other read sensors. The servo tracks may be arranged into a plurality of annular bands, with the STP in each band being fixed and different from the STP in the other bands.

Claims15

Dependent claims

A two-dimensional magnetic recording (TDMR) disk drive comprising:

a magnetic recording disk comprising
a substrate;
a recording layer on the substrate;
a plurality of radially spaced servo tracks on the recording layer and having a plurality of angularly spaced servo sectors extending across the servo tracks, the servo tracks having different track pitches at different radial positions;
a sensor carrier supporting at least two read sensors, the read sensors supported on the carrier with a cross-track offset (CTO) and an along-the-track offset (ATO);
and
a rotary actuator connected to the carrier for moving the read sensors radially, whereby the read sensors make a skew angle θ with the tracks that varies with radial position.

4 more elements

Dependencies are inferred from the claim text.

Two-dimensional magnetic recording (TDMR) disk drive with varying servo track pitch

Life of this patent

Two-dimensional magnetic recording (TDMR) disk drive with varying servo track pitch

Life of this patent

Abstract

Claims15