Hitachi perpendicular recording
This is the highest areal density achieved to date based on vertical recording. This accomplishment represents a doubling of today’s highest data densities on longitudinal recording technology. At the current rate of growth, Hitachi expects to see products shipping at 230 Gb/in2 in 2007, translating into storage capacities of up to 20 gigabytes* on Hitachi’s one-inch Microdrive and up to one terabyte on the Hitachi 3.5-inch Deskstar hard drive.
One of the key challenges facing the hard drive industry is overcoming the constraints imposed by the superparamagnetic effect, which occurs when the microscopic magnetic grains on the disk become so tiny that they interfere with one another, thus losing their ability to hold their magnetic orientations. The result is “flipped bits” – bits whose magnetic north and south poles suddenly and spontaneously reverse – that corrupt data, rendering it and the storage device unreliable and thus unusable.
Perpendicular recording definedLongitudinal recording, as its name indicates, aligns the data bits horizontally, parallel to the surface of the disk.In contrast, perpendicular recording aligns the bits vertically, perpendicular to the disk, which allows additional room on a disk to pack more data, thus, enabling higher recording densities.* 1 gigabyte = 1 billion bytes