Making Better Hard Drives with Helium

Helium Hard Drive

Helium is a wonderful element, with many uses that improve our lives outside of making balloons float and creating comedic gold when inhaled. Helium is used to cool the magnets in MRI scanners, act as a protective gas in the production of titanium, and help detect leaks in pipelines.

Now, helium is being used to make better hard drives.

Recently, Western Digital subsidiary HGST announced they shipped the world’s first ever helium-filled hard disk drive, the Ultrastar He6. Instead of being filled with air like any other drive, this drive is hermetically sealed and filled with helium. As a result of being filled with a gas 1/7th the density of air, the drive is lighter, only uses 5.3 watts of electricity when idle, and runs 7-9°F cooler than other high-capacity drives. Also, since the drive is hermetically sealed, it can be fully submerged in liquid, allowing for better cooling.

The biggest benefit though? It fits a whopping 6 terabytes of storage capacity in a 3.5” drive, when high-capacity HDDs of that size normally top out around 4 TB.

How Does a Drive Get 6 TB of Space?
You can increase the storage capacity of an HDD while keeping its 3.5” size by giving it:

More Platters – The Ultrastar He6 gets its boost in storage capacity by having seven platters, instead of the five that high capacity HDDs typically have.

Smaller Tracks – Space on a platter is finite, so smaller tracks on a platter mean that you can fit more of them, giving you additional storage space.

Both of these benefits require the same thing – smaller read-write heads.

An HDD’s read-write head functions like the needle on a vinyl LP. Heads take up space inside an HDD, and need ample space to move around in. High-end drives typically have two heads per platter, one for each side, so having smaller heads means more space for platters. Also, smaller heads can better fit into smaller tracks without fault. Bigger heads trying to fit into smaller track would mean less precision and more read/write errors.

So why not stick smaller heads in every drive?


The ability of the heads to move freely around the platter is crucial for performance and long term reliability. When you have platters spinning at RPMs in the thousands, and heads needing 100% precision when keeping up with them, a lot of air friction is generated. Friction, like with any device with moving parts, is bad news.

Friction causes positioning and read-write errors, and consequently contributes to long-term wear and tear by generating heat. If you simply decrease the size of the read-write heads while keeping the same level of air resistance in a drive, the heads would have more force acting against it as it cuts through the air. As time passes that additional effort the heads have to expend to function will reduce the performance and lifespan of the drive.

Enter Helium

Having a much less dense gas inside the drive like helium means that less effort is expended overcoming air resistance, making smaller heads less of a risk. Since helium is 1/7th as dense as oxygen, there are a lot fewer gas particles that the platters and heads have to cut through in order to function, greatly reducing friction.

Helium Hard Drives in the Future

Currently, the Ultrastar He6 is meant for enterprise hard drive needs, like data centers, so it’s not going to be available at your local Best Buy for the time being. Since it’s a new HDD manufacturing process, hermetically sealing drives filled with a gas more expensive than air, those who do buy it will be paying a premium, even with the 50% extra storage. However, the success or failure of this drive at the enterprise level will go a long way to determining if consumers will one day be grabbing helium hard drives off of Newegg.