System Design for Readback Above 1 Tbit/ ${\rm In}^{2}$ From Granular Media

The performance of a rotated sense head is examined for densities of 2-7 Tbits/ in² recorded on granular media, such as that envisioned for 2-D magnetic recording. The key idea is that tightly placed shields are used to guarantee the resolution in the cross-track direction, and oversampled signal processing regains the lost resolution in the down-track direction. It also avoids the necessity for a complex 2-D detector and head array, or latency issues if a single head were employed in the normal orientation. Simulation shows that the new design achieves a density gain of 1.7X (single head) and 2.1X (head array) over a normally oriented single head at a target bit error rate (BER) of 10^-3 with sampling period of 2 nm, minimum mean square error equalizer, and Viterbi detector. The new design shows greatly reduced BER relative to a normally oriented single head for all densities, including a very few grains per channel bit .