Hard disk drive vendors, looking beyond serial technologies, are developing even more advanced technologies to improve the physical data recording capacities of HDD magnetic media.
Many HDD manufacturers, including Hitachi Data Systems, IBM and Seagate Technology, are exploring a new magnetic recording technology called perpendicular data recording. Based on its potential capacity boosts, eWEEK Labs believes this is the shape of HDD storage to come, although it probably wont emerge for several years.
In todays “longitudinal” HDD products, data bits are recorded on magnetic mediums using a recording method in which data bits are placed parallel to the media plane. Current recording techniques can carry storage densities beyond 100 gigabits per square inch, but new recording methods will be necessary in coming years to maintain the growth rate in HDD capacity, industry experts said.
To achieve higher storage capacity, drive makers must increase the areal density of the magnetic media. Current methods involve making data bits smaller and placing them closer together, but there are several factors that can limit how small the data bits can be made.
As the data bits get smaller, the magnetic energies holding the bits in place also decrease and thermal energies can cause demagnetization over time, leading to data loss. This phenomenon is called the superparamagnetic effect. To counter it, HDD manufacturers can increase the coercivity (the magnetic field required for the drive head to write the data on the magnetic media) of the disk.
However, the amount of coercivity that can be applied is determined by the type of magnetic material used to make the head and the way the data bits are written—and vendors are approaching the upper limits in this area.
Perpendicular recording places data bits perpendicular to the magnetic media surface. The data bits are formed in upward or downward magnetic orientation corresponding to the 1s and 0s of digital data. Perpendicular recording gives hard drives a much larger areal density in which to store data because it can achieve higher magnetic fields in the recording medium.
HDD vendors have been harnessing current technology to double their drive capacities every year, and advances in Serial ATA and SCSI drives will make large storage systems cheaper, faster and more efficient than before.
We therefore dont expect to see HDD systems that use perpendicular recording technology for several years, but this recording method will take future HDD systems to densities many times greater than the current longitudinal recording methods. Some experts estimate this new recording method can create areal density up to the terabit-per-square-inch range.
Imagine being able to store terabytes of data in your iPod or handheld devices—the possibilities are almost endless.
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