Western Digital said demand for high-capacity data centre disk drives will keep up over the next few years as it told the world it would begin shipping samples of its new MAMR 18 and 20TB drives over the next four months.

The Ultrastar data centre DC HC550 is a helium-filled drive in 16TB and 18TB versions. It uses either eight or nine platters and has conventionally recorded tracks. The 20TB DC HC650 has nine platters and uses shingled magnetic recording (SMR), with zones of partially overlapping tracks, to cram in an extra 2TB of capacity over the HC550.

Current PMR (perpendicular magnetic recording) technology is reaching an areal density limit as the bit areas become too small to sustain a stable magnetic polarity. Microwave-assisted magnetic recording technology, or MAMR, uses a more stable recording medium which can sustain smaller bit areas. But writing data now involves beaming microwave energy at the bit area to enable the magnetic polarity to be set by the read/write head.

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WD revealed to us that it has a four-model range of data centre drives.

The HC330 is the only 10TB air-filled drive with as few as six platters, it said. The storage firm said 14TB drives were the present market sweet spot, citing TrendFocus research predicting this will be the dominant capacity point through to mid-2020.

WD also has a 15TB HC620, which uses shingling, but there is no pure 16TB drive in this list. Toshiba has a 16TB drive in its lineup, as does Seagate with a 16TB Exos. Bergey said WD is skipping the 16TB level to progress straight to these 18TB and 20TB capacity drives.

The company is hoping its host-managed SMR drives will become popular, estimating that half of its disk drive exabytes shipped would be on SMR by 2023.

It also said it expected demand for high-capacity data centre disk drives to be sustained for several years, despite predictions they could be seen off by SSDs using QLC (4 bits/cell) or PLC (5 bits/cell) flash. Referring to TrendFocus estimates again, the firm said it expected exabyte shipments for the disk drive industry to grow 36 per cent annually between calendar 2018 and calendar 2023.

HC330 and HC530 drives are available now. WD will sample the HC650 and HC550 drives to select customers by the end of the year, with qualification and volume shipments beginning in the first half of 2020. In other words, volume ships of these drives could be up to nine months away. ®