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Hard disks: 24-TByte HDDs require more disks

In Japan, Hoya is gearing up for increased demand for glass magnetic disks, since HAMR-based HDDs is the future.

An Exos hard disk with HAMR technology and 20 TByte
(picture: Seagate)

During the discussion of the quarterly figures (PDF), Hoya’s head of technology Eiichiro Ikeda made a few statements about upcoming hard disks: According to the CTO of the platter manufacturer, manufacturers such as Western Digital will have to use more platters for their 22 TByte and 24 TByte models than before – or they will have to use glass instead of aluminium discs

Western Digital’s Ultrastar DC HC650, for example, is a helium-filled drive with nine platters that secures 20 TByte. The US manufacturer uses so-called Energy Assisted Magnetic Recording (EAMR), which according to Western Digital is a subgroup of Microwave Assisted Magnetic Recording (MAMR). EAMR works with temporary magnetic fields, so the aluminium plates that have been in use for years can still be used.

The situation is different with Seagate, because they already use HAMR (Heat Assisted Magnetic Recording): For this storage method, glass plates are required, since the write heads heat them by laser. Hoya has already taken precautions and in 2019 has laid the foundation stone for a new plant in which glass plates for HDDs are to be produced. Such platters are thinner and lighter as well as stiffer, which is why more of them fit into a housing and increase the capacity while maintaining the same dimensions.

HAMR roadmap (Picture: Seagate)

22 TByte or 24 TByte can be built with nine glass plates and HAMR, for EAMR/MAMR more magnetic plates have to rotate in the housing to reach this capacity. Hoya assumes that all manufacturers will rely on HAMR in the medium term – which Seagate and Western Digital have also repeatedly operated with public roadmaps. Seagate plans to ship the first HAMR hard drives with 20 TByte from December 2020, Western Digital wants to offer HAMR/MARM-based drives only from 2023 onwards.

Read the original article here.