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Chinese 'Super Disk' shrinks data centre storage capacity into DVD-sized

For data centers that manage large volumes of information in AI era, optical discs remain an indispensable storage medium.

February 23, 2024
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The China Academy

“Disc” may evoke a sense of nostalgia as optical drives and CDs gradually fade from daily use. In an era where digital data accumulation is skyrocketing, traditional data storage solutions like hard drives and cloud services have largely overshadowed optical disks such as CDs and DVDs in everyday use. Yet, for data centers that manage large volumes of information, optical discs remain an indispensable storage medium. Traditional optical data storage is cost-efficient and durable, while it has been limited to single-layer data storage, significantly capping its capacity. Recognize this; a Chinese team has led to a groundbreaking development in optical storage technology—a transparent “Super Disc” capable of storing data equivalent to 100 commercial hard drives, with a lifespan of at least 40 years.

Published in the journal Nature, this innovation hails from the collaborative efforts of the Shanghai Institute of Optics and Fine Mechanics and University of Shanghai for Science and Technology, among others. The Chinese team’s breakthrough comes from creating a multi-layered, three-dimensional architecture that allows data storage across hundreds of layers, with a single disc’s capacity reaching the petabyte level (1Pb = 1000Tb). This technology stores an equivalent of about 5.8 billion indexed web pages or, to put it in perspective, a data set that would require an area the size of an average playground if stored using 1-terabyte hard drives.

The principle behind optical discs is straightforward—using finely etched grooves on a reflective surface to represent data. Yet, the challenge has always been to overcome the optical diffraction limit that caps conventional commercial disc capacities at around 500GB.

The quest to break this limit and shrink the size of data points without interference has been a long-standing pursuit in optical storage. Nobel Laureate Stefan W. Hell’s work in the 1990s on stimulated emission depletion microscopy proved that it was possible to break the optical diffraction limit, a concept the research team applied to achieve super-resolution in laser writing technology.

The breakthrough in storage capacity stems from a pioneering dual-beam control technique that surpasses the optical diffraction limit, allowing data to be densely packed into nanoscale points. This achievement enables storing data in points that are merely 54nm in size and spaced only 70nm apart. By adopting a 3D stacked architecture, the storage density is further amplified across 100 layers in each disk, significantly enhancing the total storage capacity.

With the global data volume projected to reach 175 zettabytes by 2025, the demand for more efficient storage solutions has never been more acute. The “Super Disc” technology minimizes frequent data migration—a costly and risky process required by current data centers every three to ten years to avoid data tampering or loss. Moreover, this new storage solution promises a lifespan of 50 to 100 years, significantly reducing the environmental and economic costs associated with data storage.

One of the most compelling advantages of this new technology is its energy efficiency. According to Professor Wen Jing, one of the study’s corresponding authors from University of Shanghai for Science and Technology, energy is only required when writing to or reading from the disc, not for long-term storage. This inherent property of optical data storage could drastically reduce the energy consumption of data centers, which, in China alone, amounted to 270 billion kilowatt-hours in 2022—nearly triple the output of the Three Gorges Dam, the world’s largest power station.

Looking ahead, the team aims to refine the technology further, improving data writing and reading speeds while reducing energy consumption. The ultimate goal is to make this “Super Disc” commercially available, offering individuals, families, and organizations an affordable, reliable, and capacious data storage solution. This could revolutionize how we store and manage data, from personal databases of photos, videos, and documents to the backbone of the global digital economy’s data centers.

In a world where data is as valuable as gold, the advent of the “Super Disc” marks a monumental milestone in our quest to harness, store, and preserve the ever-expanding digital universe for generations to come.

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The China Academy
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