HGST - formerly Hitachi's disk unit - announced a major advance in disk capacity and efficiency with their development of helium-filled disk drives. The drives enable greater density in both platters and bits, run cooler and are more energy efficient.

It's a major win for disk technology.

The numbers

HGST says that the new, helium-filled sealed-drive platform reduces power consumption by 23% compared to an equivalent air-filled drive side-by-side. It also enables them to add 2 additional platters - for a total of 7 - to their 3.5" disks, which should mean ≈6TB drives.

The drives also run 4°C (7°F) cooler. They calculate that the total improvement in watts-per-TB is 45 percent, which they expect to improve as the helium-filled drive platform enables higher drive capacities in future products.

The science

Drive engineers have long known that the air inside drives creates turbulence and drag that degrades performance and efficiency. The problem has been what to do about it.

Drives today are not hermetically sealed: they have a filtered air channel to allow pressure equalization between the outside and inside of a drive. HGST engineers have evidently figured out 3 things:

How build a drive structure stiff enough not to flex with pressure changes. How to seal in helium, a gas known for its remarkable diffusion properties. How to manufacture such drives in high volume at - one hopes - a competitive price.

The only things better than helium in a drive are hydrogen - which is flammable - or a vacuum - which would need a stiffer, heavier and more expensive frame.

They said it took 6 years of development. I believe it.

The Storage Bits take

While we're waiting for the drive engineers to perfect heat-assisted magnetic recording (HAMR) and patterned media - key technologies for the next major jump in recording density - helium-filled drives will enable higher density and larger capacity drives for years to come.

The major buyers will likely be large cloud storage providers, where a 45% increase in energy efficiency per TB will pay major dividends in power and cooling costs. But expect the technology to spread to all drives over time as it is perfected.

There will be a price to pay: helium is more expensive than air; and a stiffer, diffusion-proof disk structure will also have costs. But with volume both costs should drop over time.

It's great to see this kind of basic R&D come to fruition. Congratulations to the HGST engineering teams.

Comments welcome, of course. No, helium-filled drives won't float away if they aren't tied down.