HGST, a division of Western Digital, announced what experts expect will be a 5.6TB 3.5″ form factor hard drive sometime in 2013. The new largest hard drive will contain helium rather than air and will have 7 platters. Helium is 1/7 the density of air, which much less drag on the spinning disks. It also reduces the “fluid flow” forces which buffet the heads and arms. The story is interesting enough that it’s being picked up by magazines such as SMBnation.
Disk platter wobble or vibration is a significant factor in limiting hard drive storage density. The spinning motion causes air turbulence, which in turn disrupts both the platter and the read/write head’s ability to remain on track. With helium the turbulence is reduced, allowing the drive to pack more bits onto the platter while still allowing precise head positioning.
HGST also plans to pack 7 platters into the enclosure rather than only the 5 used for current 4TB drives. The helium inside will lead to less power usage and cooler drive operation. The company says power usage is lowered by 23% by using helium and that the drive runs 4 degrees Celsius cooler. Using helium along with heat-assisted magnetic recording may lead to 60TB drives by 2016.
Helium is becoming a scarce commodity, as only 6 companies in the world refine and supply it. It is extracted in small percentages from certain natural gas deposits. Once Helium is released (as when a balloon pops) it escapes into the atmosphere and is gone from earth forever. Today there are only about 15 known sources of helium in the world and 10 of these are in the United States, largely controlled by the Bureau of Land Management (BLM). Planned and unplanned outages throughout the world along with changes in a U.S. law called the Helium Privatization Act of 1996 (HPA) have impacted these limited supplies. 20% of the entire world’s output of helium is used for MRI machines and about 17% is used in welding. Another chunk is used to manufacture LCD screens. Helium price and availability could become an issue in manufacturing although it is unknown whether the small volumes used in hard drives will significantly impact the supply chain.
HGST plans to concentrate initially on the enterprise and data center market. This, along with the Helium discussion above, suggests the drive will come at a price premium above the desktop drives shipped today.
As for reliability of this new technology, we’ll have to put our trust in the engineers and then see how they do in the field. Very sophisticated and tightly controlled seals will be needed since the molecules are very small and will leak out of the smallest openings easily. We wonder if drives will ever need to be “refilled” to maintain and freshen the helium as is the case with some air conditioning systems. We’ll also have to wait to see whether the drives are robust enough to be used in removable drive backup systems like the RAIDFrame.