Hitachi shows perpendicular recording density to 610Gb / square inch is possible


Per­pen­dic­u­lar record­ing (or Per­pen­dic­u­lar Mag­net­ic Record­ing, PMR) is a recently imple­men­ted tech­no­logy for data record­ing on hard disk

The main chal­lenge in design­ing mag­net­ic inform­a­tion stor­age media is to retain the mag­net­iz­a­tion of the medi­um des­pite thermal fluc­tu­ations caused by the super­para­mag­net­ic lim­it. If the thermal energy is too high, there may be enough energy to reverse the mag­net­iz­a­tion in a region of the medi­um, des­troy­ing the data stored there. The energy required to reverse the mag­net­iz­a­tion of a mag­net­ic region is pro­por­tion­al to the size of the mag­net­ic region and the mag­net­ic coer­civ­ity of the mater­i­al. The lar­ger the mag­net­ic region is and the high­er the mag­net­ic coer­civ­ity of the mater­i­al, the more stable the medi­um is. There is a min­im­um size for a mag­net­ic region at a giv­en tem­per­at­ure and coer­civ­ity. If it is any smal­ler it is likely to be spon­tan­eously de-mag­net­ized by loc­al thermal fluc­tu­ations. Per­pen­dic­u­lar record­ing uses high­er coer­civ­ity mater­i­al because the head’s write field pen­et­rates the medi­um more effi­ciently in the per­pen­dic­u­lar geo­metry.” — Wiki­pe­dia

Hita­chi, Ltd. is work­ing on per­pen­dic­u­lar record­ing tech­no­logy and made improve­ments to it. Finally on 31st, July 2008, Announced that the max­im­um stor­age dens­ity pos­sible is 610 Gb/​square inch. This is far bet­ter than cur­rent tech­nique. It leads 2.5x times HDD capa­cit­ies that are cur­rently avail­able. This tech­nique also shows the evid­ence that hard drive capa­cit­ies have the poten­tial to advance at a rate of 40% annually.

These res­ults are based on many years of exper­i­ence with design optim­iz­a­tion and mater­i­al tech­no­logy for per­pen­dic­u­lar record­ing heads and media. We applied this know­ledge to the devel­op­ment of heads and media with an ultra-nar­row track pitch of 65nm, indis­pens­able in achiev­ing a record­ing dens­ity of 610 Gbit/​in2. Devel­op­ment of iter­at­ive sig­nal pro­cessing tech­no­logy for high dens­ity record­ing fur­ther increased dens­ity and capa­city,” said Hiroaki Odawara, Research Dir­ect­or, Stor­age Tech­no­logy Research Cen­ter, Cent­ral Research Labor­at­ory, Hita­chi, Ltd.

Hita­chi GST demon­strated 230 Gbit/​square inch. in April 2005, 345 Gbit/​square inch. in Septem­ber 2006, and has now shown extend­ab­il­ity to 610 Gbit/​square inch. These new meth­ods are still being developed, but hold poten­tial for much great­er advance­ments in areal dens­ity growth.

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