Western Digital’s HGST unit announced on September 9 that the company has begun to ship a new version of its helium-filled disk drive, the Ultrastar He8—with 8-terabytes of data storage capacity. And the company has an even bigger capacity drive waiting in the wings. That drive, which uses a new magnetic recording technology, will have a capacity of 10 terabytes.

Seagate began shipping its own non-helium 8TB drive in August, cramming more capacity onto five disk platters (though the company has said little about the recording technology used to achieve that). HGST’s 8TB drive, however, uses pressurized helium to help it cram two more disks into the drive, while still relying on widely used perpendicular magnetic recording (PMR) technology.

That isn’t the case for the next drive in HGST’s arsenal. The 10TB drive, now being “sampled” to select customers, is based on “shingled magnetic recording” (SMR)—a technology that partially overlaps data tracks like roof shingles.

Sadly, you probably won’t be seeing a 10TB drive in your desktop or notebook PC any time soon.

Because of the way its tracks are laid down, SMR is better suited to continuous writing and erasing of data, such as writing log files, storing a constant stream of images, or handling “big data” stores like Hadoop. They’re less well suited to the short, random reads and writes of typical applications.

Still, SMR pushes the potential density of storage media up to 3 trillion bits per square inch of disk platter, compared to the 200 gigabits per inch of PMR. That means that customers who have to keep huge quantities of “cold” data—such as the millions of images that Facebook users post each day—will be able to squeeze significantly more capacity into their already bulging storage systems.