Want a 70TB HDD before 2030? Seagate researchers may have reached the holy grail of 7TB per platter

• Seagate prototypes achieve 7TB per platter, the highest density for HDD research
• Ten-platter drives enable experimental HDDs to reach 70TB total capacity
• HAMR uses localized heating to write data on smaller magnetic bits

Seagate Technology has announced plans to commercialize a 3.5-inch HDD with a total storage capacity of 70TB.

This follows research-level prototypes achieving 7TB per platter, the highest areal density reported for an HDD prototype.

The company presented these results at a symposium organized by the Japan HDD Association and a seminar hosted by the National Institute for Materials Science.

Technology behind ultra-high capacity

According to Seagate, this achievement is a critical step toward reaching 10TB per platter by 2028.

The prototype drives rely on a combination of heat-assisted magnetic recording (HAMR) and shingled magnetic recording (SMR).

HAMR uses localized heating to write data on smaller magnetic bits, while SMR partially overlaps tracks to increase storage density.

These innovations build on perpendicular magnetic recording (PMR), which has been used for roughly two decades to improve areal density but is now reaching practical limits.

Additional supporting technologies include granular ferromagnets made from iron-platinum, glass substrates for platters, and multi-sensor magnetic heads with two read heads.

Together, these innovations allow prototypes to reach densities near 8TB per platter, with projections suggesting up to 10TB per platter once HAMR and SMR are fully optimized.

Seagate’s development roadmap shows steady improvements in platter density over the past decade.

Capacities increased from 3TB per platter in 2018 to 6TB in 2024, largely driven by successive generations of HAMR technology.

At the same time, increasing the number of platters in high-capacity drives has contributed to total storage growth.

Ten-platter drives are now common for experimental ultra-high capacity HDDs, positioning them to become the largest HDDs commercially available by the late 2020s.

Combining these innovations with optimized read/write technologies also makes these drives among the fastest HDDs currently in development.

HAMR technology has steadily increased areal density from 1.3 Tbit/sq inch in 2017 to 3.7 Tbit/sq inch by the first half of 2025 when combined with SMR.

Projections indicate that 10TB per platter drives are theoretically feasible within a few years.

Beyond that point, achieving 15TB per platter will require breakthroughs such as full bit-patterned media to isolate magnetic bits completely.

Seagate’s research indicates a realistic, although still experimental, path toward the best HDDs in terms of capacity.

While 70TB drives may now appear achievable by late 2025 or early 2026, the timeline for commercially available 10TB per platter drives remains uncertain.

Via PC Watch (originally in Japanese)

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