12TB and 14TB drives are also on the horizon.

Good news if you like big hard drives: Seagate announced on an earnings call yesterday (as reported by PC World) that it has both 14TB and 16TB versions of its helium-filled spinning hard drives in the pipeline for the next 18 months. A 12TB version of the drive is "being tested" and should be ready sooner rather than later.

And the push for ever-higher capacities will continue after that—Seagate wants to have a 20TB drive ready by 2020, and it would like to push the minimum capacity for drives shipping in new PCs to 1TB. 500GB drives are typical in entry-level models these days.

Seagate still slightly trails some of its competitors here—HGST beat Seagate to market with the 10TB version of its helium-filled hard drive, and HGST already has a 12TB version of the same drive on the market. But Seagate's drives tend to be cheaper than HGST's, and while HGST drives have lower failure rates according to Backblaze's drive reliability data, Seagate's reliability has greatly improved in recent years. Larger hard drives make it possible to increase the capacity of a server or a home NAS unit without actually needing more physical space.

SSDs have fallen in price to the point where they're becoming the default storage options even in midrange PCs, and they're also far outstripping spinning hard drives in terms of raw capacity—it's easier to make a 60TB hard drive when you can just stuff a 3.5-inch enclosure with NAND chips instead of platters and helium—but spinning HDDs are still the most cost-effective way to get a bunch of capacity. Seagate's current 10TB hard drives start just north of $400, much less than the price of a typical 2TB SATA SSD.