Western Digital's HGST division has released the world's first helium-filled 10TB hard drive for everyday use—assuming you have about £600 burning a hole in your pocket, anyway. Meanwhile, despite reiterating that it would have a 10TB drive on the market this year, Seagate hasn't yet moved past the 8TB mark.

The Ultrastar He10 is notable for two reasons: it's hermetically sealed and filled with helium, which is still a rather novel idea; and it has seven platters crammed into a standard-height 25.4mm (1-inch) hard drive.

The platters themselves are impressive, too: instead of using shingled magnetic recording (SMR) to boost areal density, these platters use conventional perpendicular magnetic recording (PMR). PMR has been the standard hard drive recording tech since 2005, when it replaced longitudinal recording. The move to PMR has increased the maximum platter density by an order of magnitude—from about 100Gb per square inch to 1000Gb—but now, alas, we're beginning to hit the limits of PMR.

SMR has emerged as one possible way of increasing hard drive storage density, but the way it works—by overlapping magnetic tracks, like roofing shingles—makes it better suited to archival or nearline use, rather than 24/7 online use.

Beyond PMR, the next recording technology to be commercialised will probably be HAMR: heat-assisted magnetic recording. Both Seagate and HGST are working on HAMR tech, which uses a laser to heat up a small region of the hard drive that's being written. The heat causes the magnetic grains to lose their superparamagnetic effect for a short period, allowing for smaller magnetic grains and higher areal density. Superparamagnetism is an annoying trait of magnetic nanoparticles where they randomly flip direction—a problem when, for example, this results in your binary zeroes randomly becoming binary ones.

Earlier this year, Seagate released an 8TB drive with SMR, and HGST released a 10TB SMR drive. Today's Ultrastar He10 is the first 10TB drive with PMR. Seagate hasn't yet managed to squeeze seven platters into a 3.5-inch hard drive, which appears to be why Seagate is lagging behind HGST in the capacity race. There are a few reasons why Seagate hasn't hit seven platters yet, but HGST's use of helium, which offers significantly less air resistance to the spinning platters, is probably the main one.

Both HGST and Seagate are working on HAMR drives, though Seagate has been more vocal about it, saying that it could have some HAMR drives on the market in 2016. HGST, with shingled recording and seven platters at its disposal, should have no problem hitting 15 or 20TB over the next year—but its path towards larger online drives, using PMR or HAMR, is unclear.





There's no price listed for the Ultrastar He10, but it'll probably cost about £600/$800. The first helium-filled drives were extortionately expensive, but the He8 is now down to around £400/$550, which isn't bad for an enterprise drive (these things have a 5-year warranty and other such niceties, too). Seagate's shingled 8TB drive is much cheaper (£170/$200), but you get a shorter warranty and less enterprisey stuff.