It's a hard drive ahead: Seagate hits the density problem with HAMR, WD infects MAMR with shingles

Seagate's next-generation HAMR disk drive will be a drop-in replacement while Western Digital's MAMR drive will not, The Register can reveal.

WD's technical product marketing director Eyal Shani told us that MAMR drives would use host-managed shingling, and so would not be drop-in replacements for existing drives.

With shingling, write tracks are partially overlapped, meaning any rewriting of already written data incurs a time penalty as the affected block of write tracks is read, altered with the new data, and then rewritten.

Shani said shingling added between 16 per cent and 25 per cent additional capacity beyond the iMAMR increase. A 20TB MAMR drive in non-shingled form would be a 15TB to 17.2TB capacity drive, not a 20TB one. Western Digital has hyperscaler customers like Dropbox in mind for its MAMR drives.

Western Digital has said it will will ship both shingled and non-shingled MAMR drives, commencing later this year.

He also revealed WD is developing dual-actuator technology to increase disk drive IO rates. The first actuator will handle the high four platters and the second looks after the lower four platters. We expect a statement on availability in June 2019.

Meanwhile, Seagate CEO Dave Mosley told a Morgan Stanley Technology, Media and Telecom conference earlier this week that a Seagate HAMR drive "looks like a normal drive so it looks like the other drives that are out there".

That means it will be a drop-in replacement for existing PMR drives. El Reg's storage desk suggests the next-generation capacity disk drive market could split between on-premises non-shingled HAMR drives and shingled MAMR drives for hyperscalers. ®