Western Digital Unveils 20TB HDD with OptiNAND Technology

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Western Digital improves hard drives with OptiNAND.
Western Digital has introduced the industry's first 20TB hard drives that integrates an iNAND UFS embedded flash drive (EFD) to improve performance, reliability, and capacity. The company's OptiNAND architecture does not use 3D NAND memory for caching, but to store various metadata to enhance key characteristics of hard drives.

Western Digital's 20TB HDDs with OptiNAND technology are based on nine 2.2TB ePMR (energy-assisted perpendicular magnetic recording technology) platters, triple-stage actuator technology for more precise positioning of read/write heads, an iNAND UFS drive of unknown capacity that uses 3D TLC NAND memory, and the company's custom system-on-chip (SoC) that controls the drive as well as communication between the HDD and the EFD.

Modern hard drives store gigabytes of metadata on spinning media since it cannot be cost-effectively stored in local DRAM and serial NAND. HDDs store repeatable runout (RRO) metadata (the share of the position error signal that is repeatable for every spindle revolution) as well as write operations metadata at the track level to account for increased adjacent track interference (ATI). With OptiNAND, RRO and write operations are stored on the iNAND drive, which frees up space on the rotating media, faster metadata availability, and reduces the number of read/write metadata-related operations, which further improve performance (e.g., random read/write performance).…
Anton Shilov
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