This should be a gas for the storage-hungry: Western Digital's HGST unit, which makes disk storage for the enterprise market, has begun shipping helium-filled 3.5-inch hard drives with a massive storage boost. The new drives have six terabytes of storage capacity—50 percent more than that of conventional drives of the same size.

The technology required to keep the helium reliably sealed within the drives, called Helioseal, has been in development by HGST for over 10 years. The company initially announced this commercial development in September of 2012. The use of helium rather than air allows additional storage platters to be squeezed into the design, nearly doubling their capacity with existing storage media technology while reducing power consumption and weight.

The new six terabyte Ultrastar He6 fits seven disk platters into the same form factor as HGST's previous five-platter/four terabyte drive. In addition to half again as much capacity, the drives run considerably cooler than conventional drives—as much as four to five degrees Celsius cooler, greatly reducing heat output. These drives even consume 23 percent less power at idle, drawing just 5.3 watts

All that comes at a price premium per drive, so don't expect these drives to show up in your laptop anytime soon. Just how much of a premium, however, HGST hasn't said yet. While the drives are now generally available, a link to a data sheet on the drives currently yields a "Lotus Notes Exception" error.