This week Western Digital-owned HGST announced that its new 6 TB Ultrastar He6 hard disk drive is now shipping. This isn't just any hard drive, though. The Ultrastar He6 uses HGST's HelioSeal, which means the spinning platters are sealed inside a hermetic chamber filled with helium instead of air.
The density of helium is one-seventh that of air. The use of helium in HGST's new drive equates to dramatically less drag force acting on the spinning disk stack and a substantial reduction in mechanical power from the motor. The lower helium density also means that the fluid flow forces buffeting the disks and the arms, which position the heads over the data tracks, are greatly reduced. This allows for disks to be placed closer together (seven disks in the same enclosure) and to place data tracks closer together (allowing continued scaling in data density). The lower shear forces and more efficient thermal conduction of helium also mean the drive will run cooler and will emit less acoustic noise.
The Ultrastar He6 boasts 5.3 idle watts and weighs in at 640 g (HGST claims that the Ultrastar He6 packs a 38 percent lower weight-per-TB compared to a 3.5-inch, five-platter, air-filled 4 TB drive). It's designed for cloud storage, massive scale-out environments, disk-to-disk backup, and replicated or RAID environments.