Seagate has started shipping the first 16 TB PMR hard drives.

"We are very pleased to announce that we began shipping our 16 terabyte drives in late March as planned. We are delivering the industry's highest capacity disk drives to enable improved performance at the lowest total cost of ownership for our customers. Qualifications are underway at many major cloud and enterprise customers. We expect to begin ramping to high volume later in calendar 2019 and expect 16 terabyte drives will be our highest revenue SKU by this time next year," Seagate CEO Dave Mosley said
during he company's quarterly earnings call last week.

These drives do not use next-generation heat assisted magnetic recording (HAMR) technology. Instead, they're based around more contemporary perpendicular magnetic recording (PMR), which is being boosted by two-dimensional magnetic recording (TDMR). These 16 TB 3.5-inch helium-filled hard drives are using nine PMR+TDMR-based platters. The previous Seagate drives features eight platters. Toshiba has used a nine-platter architecture for a while now.

In addition to its Exos X16 PMR+TDMR hard drives, Seagate is also getting ready to release host-managed 18 TB SMR (shingled magnetic recording) HDDs, which is powered by the same platform.

"...Different drives going from 6 to 8 to 10 to 12 to 14 we've had different drive platforms. This particular platform for us will take us 16 and 18 with SMR and other variants. It will take us beyond 18 terabytes and probably into the HAMR families as well because HAMR is basically drop into this when we're ready. So, we feel very comfortable with our ability to yield and ramp this product. It's gone through all its interim qualification testing really well and so that's why we're fairly aggressive about it. I think it's going to be a pretty steep ramp as well. So, in the last couple of months just given the lead times for largely the head wafers that are required for that, that's where we focused a lot of our efforts internally," Mosley added.

Seagate expects to introduce drives with over 20 terabytes of capacity in calendar year 2020, based on its HAMR recording technology.