Research on extremely high capacity storage systems by perpendicular hard disk drives

High capacity storage system using perpendicular magnetic recording was investigated in order to give a solution for the bottle neck of capacity and data transfer rate of storage systems in multi-media and high speed network technology.In particular，evaluation of error rate for perpendicular magnetic recording system including signal processing was one of the most crucial issue.First heads and disks for experiments were prepared.A thin-film single-pole head on a flying slider，which could be adopted to practical application，was developed。Using the head as a write for perpendicular double layer disks，adaptability of MR head was investigated.Theoretical expression for the MR head response was derived to estimate read performance for any given head and disk。Next，read channel for the perpendicular storage was studied.We established a differential equalizer which transformed perpendicular step-like response into single peaking pulse and PRML error rate analyzer for the perpendicular head/disk system。Sufficient error rate at high densities more than300kFRPI was demonstrated.The results indicated that the single-pole head and double layer media with an MR head could be used in a practical high density storage systems.In order to increase attainable areal density，signal SNR limitation was explored.Theoretical approach employing Voronoi cell modeling for media indicated that the limitation was governed by media noise，which originated from finite size of magnetic structure of the perpendicular media.Therefore，it was predicted that fine magnetic structure brought higher signal SNR，i.e.，better error rate at high densities.By above mentioned studies，potential of perpendicular magnetic recording for areal density of 100Gbits/inch ID12文件D1has been demonstrated in association with high resolution MR head and low noise perpendicular double lmedia.

High capacity storage system using perpendicular magnetic recording was investigated in order to give a solution for the bottle neck of capacity and data transfer rate of storage systems in multi-media and high speed network technology. In particular, evaluation of error rate for perpendicular magnetic recording system including signal processing was one of the most crucial issue.First heads and disks for experiments were prepared. A thin-film single-pole head on a flying slider, which could be adopted to practical application, was developed. Using the head as a write for perpendicular double layer disks, adaptability of MR head was investigated. Theoretical expression for the MR head response was derived to estimate read performance for any given head and disk. Next, read channel for the perpendicular storage was studied. We established a differential equalizer which transformed perpendicular step-like response into single peaking pulse and PRML error rate analyzer for the perpendicular head/disk system. Sufficient error rate at high densities more than 300 kFRPI was demonstrated. The results indicated that the single-pole head and double layer media with an MR head could be used in a practical high density storage systems.In order to increase attainable areal density, signal SNR limitation was explored. Theoretical approach employing Voronoi cell modeling for media indicated that the limitation was governed by media noise, which originated from finite size of magnetic structure of the perpendicular media. Therefore, it was predicted that fine magnetic structure brought higher signal SNR, i.e., better error rate at high densities.By above mentioned studies, potential of perpendicular magnetic recording for areal density of 100 Gbits/inchィイD12ィエD1 has been demonstrated in association with high resolution MR head and low noise perpendicular double layer media.