Helium-filled hard disks will lead to higher capacities

Hitachi Global Storage Technologies (HGST), which is now a subsidiary of hard drive manufacturer Western Digital, announced yesterday that it will soon be bringing to market a sealed hard disk drive filled with helium instead of air.

Hard disk drives today are not sealed—they have breathing holes (covered inside with activated-carbon microfilters) through which air is drawn in and expelled. As the drive's platters spin, their motion drags the air inside the drive along their surface with a shearing force similar to how the bow of a boat drags water along with it, creating what's called an air bearing. The drive's read and write heads float on this air bearing just a few billionths of a meter above the drive's surface.

According to Computerworld and CRN, HGST's new helium-filled drives will contain more platters and more read/write heads than air-filled disks, which will translate to higher storage capacities. This is possible because helium is far less dense than air, and the lower density of the gas means that turbulence inside the drive (from external motion or from the movement of the head actuators themselves) will have less of an effect on the position of the read and write heads. This makes more precise head positioning possible, which translates directly to being able to read and write smaller data tracks on the surface of the platters.

How much smaller? Quite a bit—though HGST isn't releasing exact numbers, it is saying that the new technology could lead to 40 percent higher data density on the drive platters. Additionally, replacing air with helium will cause less drag on the platters as they spin, reducing the energy consumed by the drives by more than 20 percent. This isn't a huge amount of energy saved for a single disk, but a data center stuffed with thousands of the sealed helium drives would demonstrate very real cost savings over one using traditional air-filled hard disk drives. Indeed, HGST is directly positioning the drives to be used in cloud infrastructure and large corporate data centers.

Pricing and release dates aren't yet known, though HGST expects the drives to be available some time in 2013.