No abstract

The maximum recording speed of a magnetic data storage device depends on the components in the recording channel, viz. electronics, interconnects, heads and media. The projected increase in device data rate (6-fold in 5 years) is that for the electronics (silicon switchfold in 5 years). Driving the write head meets with "driving point impedance" limitations, linking the required MMF, the interconnect and head inductance, supply voltage and write current switching speed. Novel write drivers can break this link.Interconnect limitations and distributed readlwrite electronics are discussed. Write field waveforms and their dependence on the write current are presented. Various ways of improving the head switching time are treated. Finally, for the projected data rate increase to materialize, one has to solve all component limitations virtually simultaneously.

No abstract

Exponential growth of the areal density has driven the magnetic recording industry for almost sixty years. But now areal density growth is slowing down, suggesting that current technologies are reaching their fundamental limit. The next generation of recording technologies, namely, energy-assisted writing and bit-patterned media, remains just over the horizon. Two-Dimensional Magnetic Recording (TDMR) is a promising new approach, enabling continued areal density growth with only modest changes to the heads and recording electronics. We demonstrate a first generation implementation of TDMR by using a dual-element read sensor to improve the recovery of data encoded by a conventional low-density parity-check (LDPC) channel. The signals are combined with a 2D equalizer into a single modified waveform that is decoded by a standard LDPC channel. Our detection hardware can perform simultaneous measurement of the pre- and post-combined error rate information, allowing one set of measurements to assess the absolute areal density capability of the TDMR system as well as the gain over a conventional shingled magnetic recording system with identical components. We discuss areal density measurements using this hardware and demonstrate gains exceeding five percent based on experimental dual reader components.