The HDD industry is at a critical technology cross roads and it is paramount that we quickly establish comprehensive paths to push
beyond the superparamagnetic limit. Several promising technology options have been explored to increase the areal density beyond the
limit such as bit patterned magnetic recording (BPMR), heat assisted magnetic recording (HAMR), and microwave assisted magnetic
recording (MAMR). In addition to these three technology options, there is recent interest in a fourth approach that has the advantage of
staying with a relatively conventional perpendicular medium and head. This combines shingled write recording (SWR) and/or 2-D read
back and signal processing. Either technique can be used separately to give large gains and the combination of the two, which is referred
to as 2-D magnetic recording (TDMR), promises particularly large gains. Recording with energy assist on BPM or 2-D signal processing
will enable the areal density beyond around 5 Tb/in