- Seagate prototypes reach 7TB per platter, the highest density for hard drive research
- Ten-platter drives enable experimental hard drives to reach a total capacity of 70 TB
- HAMR uses localized heating to write data to smaller magnetic bits
Seagate Technology has announced plans to release a 3.5-inch hard drive with a total storage capacity of 70TB.
This follows research-grade prototypes reaching 7TB per platter, the highest areal density reported for a hard drive prototype.
The company presented these results at a symposium hosted 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 crucial step towards reaching 10 TB per platter by 2028.
The reader prototypes are based on a combination of heat-assisted magnetic recording (HAMR) and shingle magnetic recording (SMR).
HAMR uses localized heating to write data onto smaller magnetic bits, while SMR partially overlaps tracks to increase storage density.
These innovations rely on perpendicular magnetic recording (PMR), which has been used for about two decades to improve areal density, but which is now reaching its practical limits.
Additional supporting technologies include granular iron-platinum ferromagnets, glass platter substrates, and multi-sensor magnetic heads with dual read heads.
Together, these innovations allow prototypes to achieve densities close to 8 TB per platter, with projections suggesting up to 10 TB per platter once HAMR and SMR are fully optimized.
Seagate’s development roadmap shows steady improvements in platter density over the past decade.
Capacities have increased from 3TB per platter in 2018 to 6TB in 2024, largely due to successive generations of HAMR technology.
At the same time, the increase in platter counts in high-capacity drives has contributed to total storage growth.
Ten platter drives are now common for very high capacity experimental hard drives, positioning them to become the largest commercially available hard drives by the end of the 2020s.
Combining these innovations with optimized read/write technologies also makes these drives among the fastest hard drives 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 drives per platter will be theoretically feasible within a few years.
Beyond this point, reaching 15TB per platter will require breakthroughs such as full binary patterned media to completely isolate the magnetic bits.
Seagate’s research points to a realistic, if still experimental, path to the best hard drives in terms of capacity.
Although 70TB drives now appear feasible 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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