Optical storage disc as Data storage technology is making combeback

Rajesh Uppal March 3, 2023 Industry, Photonics Comments Off on Optical storage disc as Data storage technology is making combeback 736 Views

There were 79 zettabytes of data generated worldwide in 2021. By 2025, more than 150 zettabytes of big data will need analysis. Dramatic increases in data storage capacities are urgently needed as they are being outpaced by exponential growth in data generation, driven by use of the internet, social media, and cloud computing. New, long-term data storage solutions that extend beyond traditional magnetic hard disk drives or tape, and solid-state drive (SSD) storage are a must to overcome this bottleneck.

Data storage essentially means that files and documents are recorded digitally and saved in a storage system for future use. Storage systems may rely on electromagnetic, optical or other media to preserve and restore the data if needed. Data storage makes it easy to back up files for safekeeping and quick recovery in the event of an unexpected computing crash or cyberattack.

Data storage can occur on physical hard drives, disk drives, USB drives or virtually in the cloud. The important thing is that your files are backed up and easily available should your systems ever crash beyond repair. Some of the most important factors to consider in terms of data storage are reliability, how robust the security features tend to be and the cost to implement and maintain the infrastructure.

Data growth is overwhelming existing storage technologies, and today’s outdated enterprise storage technologies fail to address three key pain points of cost, cybersecurity and sustainability. The high cost of storage is untenable with exploding data growth, cyber threats continue to escalate, and data centers are a major contributor to energy/water usage and CO₂ emissions. Current hard disk drive (HDD) and LTO tape roadmaps reflect insufficient technological advancement to meet user needs and desired price points in the future.

An optical disc is an electronic data storage medium that is also referred to as an optical disk, optical storage, optical media, Optical disc drive, disc drive, which reads and writes data by using optical storage techniques and technology. An optical disc, which may be used as a portable and secondary storage device, was first developed in the late 1960s. James T. Russell invented the first optical disc, which could store data as micron-sized light and dark dots.

Optical disc

An optical disc can store more data and has a longer lifespan than the preceding generation of magnetic storage medium. Optical media is the longest lasting medium currently in production. It can reliably hold onto your data for 50-100 years without power or cooling, and without the worry of magnetic degradation.

Using recordable optical media such as DVD-R is perfectly suitable for long-term archiving because it is write-once, read-many, meaning it is physically immutable—cannot be changed—so the data on it is tamper-proof

Optical discs are impervious to most environmental threats like magnetic disturbances or power surges; however, these discs are not expensive to manufacture. It helps optical disc storage to make well-suited for archival storage.

One reason for the popularity of optical media is that it supports ISO 9660, which means it works like any other removable media that you might have used. Once a formatted BD-R disk or ODA cartridge is placed in a drive, it appears in the operating system and behaves like any other external drive. This allows you to copy using standard utilities and read the files in any other system that has a matching drive and the appropriate drivers.

Optical media is also designed with full backwards compatibility, meaning future BD-R and ODA drives will be able to read disks written in today’s drives. For example, you can read a CD-R disk written in 1991 in a current BD-R drive. In contrast, LTO-8 tape drives cannot read LTO-5 tape although they can read LTO-6 tapes.

Blu-ray vs optical disk

There are two types of optical media in use today. The most popular by far is Blu-ray Disc Recordable (BD-R), which can write at 72MB/s and read at 54MB/s. It also supports random access like a disk drive, so single file retrievals are very quick.

Blu-ray discs, which are the newest type of optical media, have the potential to store the most, up to 50 GB of data. BD-R (Blu-ray recordable) is available in the market with a storage capacity of 25 GB or 50 GB. BD-R drives are available as internal or external drives, and BD-R libraries are available with one or more drives and dozens-to-hundreds of slots for BD-R media. There are two main manufacturers of such libraries: HIT and DISC.

One downside to BD-R is that read/write speeds are governed by how quickly you can transfer data to and from a single optical disk. Sony worked around this limitation by putting several optical disks in single cartridge that are written to simultaneously, very similar to the way magnetic disk drives work. This creates a virtual disk that is bigger and faster than any individual optical disk.

One approach to boosting data storage capacities is 3D or multilayer optical data storage. As the name suggests, it involves information being recorded and read out in 3D structures such as multilayer discs, cards, crystals, or cubes. The writing and readout of information is typically achieved by focusing one or more laser beams into the 3D medium. Due to the volumetric nature of the storage medium, the laser is required to pass other points before writing or reading the desired datum. This means that a nonlinearity is typically required for both the write and readout functions so that only a single local point at a given time is addressed.

The Sony Optical Disc Archive (ODA) drive supports capacities up to 5.5 TB and a write speed of 187.5 MB/s (with verify on) and a read speed of 375 MB/s. They are available as standalone drives that support up to 165TN and scale by stacking modules to support 2.9PB. The downside is that at $9,000, a single standalone ODA drive is 90 times more expensive than its BD-R counterpart ($100).

Construction

Optical storage systems use optical disks like Blu-Ray that include a layer of reflective material. Optical drives use a laser to physically create unreflective spots called pits in an adjacent coating that can be detected by the laser that reads them. The pattern of pits and the unburned, reflective areas called lands encode the data being stored. It is physically impossible to re-burn an already-burned write-once optical disk, leading some to say optical is the only truly immutable storage option, as it cannot be changed even if someone hacked a drive.

The basic sandwich of materials structure is used by all recent optical disc formats. The base is formed by using a hard-plastic substrate, and a reflective layer of metallic foil is used for encoding the digital data. Next, a clear polycarbonate layer secures the foil and enables the laser beam to move via the reflective foil layer.

Optical discs include different materials in the sandwich, which are dependent on the type of disc, whether it is rewritable or write-once. In write-once CD-ROM, an organic dye layer is located between the polycarbonate and unwritten reflective foil. Because they replace the aluminium foil with an alloy that is a phase-change material, rewritable optical discs may be erased and rewritten several times.

Optical storage technology advancements

Optical techniques are widely believed to hold the key to increasing data storage capacities. With requirements of petabyte (PB) to exabyte (EB) storage capacities on the horizon, current optical disc technologies are unlikely to represent a viable option for high-capacity long-term archival storage. To meet the requirements of massive data warehouses, where magnetic-based storage technologies are still used, optical data storage in the mid to high terabytes (TB)- or even PB-per-device will be required. Optical data storage is particularly promising because it allows for multidimensional data storage.

At the University of Southampton, United Kingdom, 5D optical data storage technology has been demonstrated. It stores information by encoding data not only in three spatial dimensions, but also by two parameters relating to birefringence that are manipulated by the polarization and intensity of a femtosecond laser focused inside a glass medium. The method could see hundreds of TBs stored on a disc with long-term thermodynamic stability. Improvements in the data read speeds are required, however, to improve the technology’s commercial prospects. What’s more, applications might be limited due to requisite high-power laser systems and the lack of data rewritability.

Another example—this time involving hybrid glass containing gold nanorods—comes from the Royal Melbourne Institute of Technology, Australia. In a novel approach using the surface plasmon resonance properties of the gold nanorods, information is to be stored and read out by using different polarizations and wavelengths of light. But this technique that could see tens to hundreds of TBs stored in an optical medium also suffers from lack of rewritability and a requirement for high-power lasers. Still, if the difficulties can be overcome, this and other multidimensional optical data storage technologies have the potential to dramatically increase optical disc capacities by several orders of magnitude, especially for archival storage applications.

Optical data storage is also suited to multilevel encoding techniques in which storage capacity can be significantly increased by writing multiple bits per point using different discretized signal intensity levels. Multilevel data storage also increases the data readout rate as several bits are read out simultaneously, which is very important for big data sets. Multilevel encoding has been demonstrated in several polymers, but suffered from photobleaching resulting in partial erasure of the data. These techniques have also been rather limited in the number of bits that could be stored.

In an emerging technique from the University of South Australia and the University of New South Wales, data can be stored using unique properties of inorganic phosphors. The optical data storage mechanism entirely revolves around modifying the luminescence spectral fingerprint of nanocrystalline phosphors with the burning of spectral holes at different wavelengths and discretized depths.

These changes to the luminescence spectrum involve exposing the nanocrystalline phosphors to certain wavelengths of light, which allows dips in the spectrum to be created in the frequency domain. These dips can be discretized in depth to store multiple bits at multiple frequencies at room temperature.

This approach has potential to be rewritable and to use low-power lasers. The technology also doesn’t require cryogenic temperatures, instead allowing spectral hole burning at room temperature making data storage with this approach significantly more practical. By dispersing such nanocrystalline phosphors into 3D media such as glass blocks, storage capacities approaching hundreds of TBs to PBs can be predicted.

“With large companies such as Google and Facebook taking an interest in optical discs for archival data storage applications, the optical disc is set to make a comeback in commercial applications. If, indeed, tens- to hundreds-TB optical discs can be realized economically, consumer applications are likely to follow,” writes Nicolas Riesen is a senior research fellow at the University of South Australia, a founder of Modular Photonics Pty Ltd., and an affiliate of TOMdisc.

Folio Photonics Announces Breakthrough Multi-Layer Optical Disc Storage Technology

Folio Photonics, a leading pioneer of immutable active archive, announced in August 2022 that it has achieved a significant breakthrough in multi-layer optical storage disc technology that will enable an unprecedented level of cost, security and sustainability advantage. Leveraging patented advancements in materials science, Folio Photonics has developed the first economically viable, enterprise-scale optical storage discs with dynamic multi-layer write/read capabilities, which will enable the development of radically low-cost/high-capacity disc storage.

“Folio Photonics is on a path to engendering far greater data densities than was thought possible several years ago,” said John Monroe, lead analyst at Furthur Market Research and former VP analyst in the data center infrastructure group at Gartner. “Using next-generation materials, patented polymer extrusion, and film-based disc construction processes (distinct from mere optical layering), in concert with customized optical pickup units (OPUs), Folio Photonics appears poised to deliver a new optical technology that enables eight or 16 film layers per side per disc, as opposed to only three optical layers per side per disc for archival discs today, with a roadmap to add additional layers over time.”

Optical Disc Market

The global Optical Disk Storage System Market is categorized on type, region, and Application. This includes Market type – Below 24TB,24-48TB,48-100TB,100-360TB,360-840TB,Above 840TB and Market application – Medical,Archival Industry,Government,IT Industry,Electric Power,Public Security,Finance,Film and Television Media,Others and Market region – North America: United States, Canada, Europe: GermanyFrance, U.K., Italy, Russia,Asia-Pacific: China, Japan, South, India, Australia, China, Indonesia, Thailand, Malaysia, Latin America:Mexico, Brazil, Argentina, Colombia, Middle East & Africa:Turkey, Saudi, Arabia, UAE, Korea.

Leading Sony, Moser Baer India, Toshiba, Fujitsu Laboratories, IBM, LG Electronics, Hitachi Global Storage Technologies, Western Digital Technologies, Colossal Storage, Samsung Electronics