Seagate has unveiled the first terabit-per-square-inch hard drive, essentially doubling the typical areal density of modern hard disks. First off, this will result in 6TB 3.5-inch desktop drives, and 2TB 2.5-inch laptop drives – but Seagate expects to expand to 60TB and 20TB drives respectively.

To have made such a big advance in drive density, Seagate incorporated a technology called heat-assisted magnetic recording (HAMR). The size of each magnetic bit in a hard drive dictates its size – these bits can only be made so small before the magnetism of other bits begins to take effect. HAMR bits are made of compounds that can withstanding further miniaturization. Fujitsu developed HAMR in 2006, and the system adds a laser to the hard drive head. The drive head seeks as normal, but when it is time for data to be written, the laser comes on.

Data is read in the conventional fashion. One terabit per square inch is roughly two million bits per linear inch, with each site being about 12.7 nanometers long – or about a dozen atoms. Theoretically, HAMR should accomodate areal densities of up to 10 terabits per square inch, which equates to 60TB, for a desktop hard drive. There’s no mention of the cost of HAMR drives, or about how the laser would affect power consumption.

Still, one might wonder what the point of local storage will become, as cloud-based storage and computing advances. But 60TB local drives, coupled with 100Mbps internet connections might also make the idea of a cloud a bit pointless as well. Though, the latter is unlikely, as smartphones and tablets with flash memory, in tandem with cloud drives might eventually make mechanical hard drives obsolete for typical computing.