A simple skew angle detection and suppression method for bit-patterned magnetic recording

Santi Koonkarnkhai,Chanon Warisarn,Piya Kovintavewat

doi:10.1063/9.0000124

Santi Koonkarnkhai, Chanon Warisarn + Show 1 more

Open Access

https://doi.org/10.1063/9.0000124

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Abstract

An achievement of an areal density (AD) up to 4 Tb/in2 in hard disk drives (HDDs) is expected under a bit-patterned magnetic recording (BPMR) system. One of major problems in HDDs is a skew angle (SA), which depends on a read/write head position on a disk platter. Practically, if precaution is not taken, the SA can easily deteriorate the overall system performance. To maintain an acceptable system performance; therefore, we present a simple SA detection and suppression method for BPMR systems. Here, one readback sequence is used to compute a specific target coefficient before employing it to estimate the SA amount. To mitigate the SA effect, a couple of suitable two-dimensional (2D) target and its compatible one-dimensional equalizer associated with the estimated SA is utilized in the data detection process. We also propose the flipped-cross-track symmetric 2D target to reduce the complexity of the detector. Simulation results reveal that the utilization of our proposed SA method can improve the bit-error rate performance when compares with the conventional system that does not use the SA detection and suppression method, particularly when SA or AD is high.

Highlights

Bit-patterned magnetic recording (BPMR) is one of the emerging technologies for next-generation hard disk drives (HDDs)
Miura et al.5 proposed a method to increase an areal density (AD) by utilizing the skew angle (SA) effect for shingled-write magnetic recording (SWMR); a large SA
This 2D impulse response is resulted from a square island with nm thick and nm long, using the MR read head with a width of 15 nm, a thickness of 4 nm, a fly height of 10 nm, and a gap distance of 16 nm

Summary

Introduction

Bit-patterned magnetic recording (BPMR) is one of the emerging technologies for next-generation hard disk drives (HDDs). A BPMR system stores one data bit onto a single-domain magnetic island, surrounded by non-magnetic material, which can increase an areal density (AD) up to 4 Terabit per square inch (Tb/in2).. Apart from the 2D interference, other disturbances such as media noise, track mis-registration (TMR), and skew angle (SA) can deteriorate the BPMR system performance, especially at high ADs. Because the SA is one of the main challenging problems inevitable in read/write processes; this paper focuses on how to lessen the SA effect. Miura et al. proposed a method to increase an AD by utilizing the SA effect for shingled-write magnetic recording (SWMR); a large SA leads to a problem of the slider flying and the read/write head offset capability.. Miura et al. proposed a method to increase an AD by utilizing the SA effect for shingled-write magnetic recording (SWMR); a large SA leads to a problem of the slider flying and the read/write head offset capability. Elidrissi et al. found that using multi-read head array can provide better performance than using a single read head in the SWMR system at different SAs

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