Next-generation desktop HDDs may come with glass platters

As the storage capacity of desktop HDDs continues to increase, manufacturers may increasingly opt for a glass substrate for the platters instead of an aluminum alloy. Glass would be advantageous for 3.5″ HDDs with more platters as well as when using the Hamr technology.

The Japanese company Hoya, the only company focused on manufacturing glass for HDD platters, expects significant growth and cites the advantages over Nikkei. The company has prototypes of 3.5″ HDDs with ten glass substrate platters with 0.5mm thickness and nine with 0.635mm thickness. Hoya already makes glass substrates for 2.5″ drives, but as laptops are increasingly equipped with SSDs, that market is shrinking for the Japanese company. In the past IBM already used glass for platters, but the company stopped doing so, partly because of the high costs.

According to the company, the rigidity of its glass substrate is higher than the aluminum alloy that manufacturers now use, at a lower thickness. This would allow HDD manufacturers to pack more platters into hard drives.

For example, WD uses eight platters for current 12TB drives, but higher storage capacities are expected to require even more platters. Toshiba and Seagate have already announced 14TB and 18TB HDDs. With current techniques, there is little stretch to further increase the storage density of the platters.

Seagate is working on a promising technique that can significantly increase storage density: hamr or heat-assisted magnetic recording. Here, the magnetic areas where data is stored are demagnetized and remagnetized under heating of a laser. According to Hoya, this requires material that can withstand the high temperatures of up to 700°C. The aluminum-based platters could withstand a maximum of 200°C, but the glass substrate would be sufficient. It is not known when Seagate will release its first disks with hamr. Initially, these would already be released in 2014.