Optical discs already offer dust and water resistance, and can withstand changes in temperature and humidity when stored. They also allow inter-generational compatibility between different formats, ensuring that data can continue to be read as formats evolve. This, the companies say, makes them a suitably robust medium for long-term storage of content.
However, with the move to higher resolutions, including 4K and 8K, discs will have to accommodate much larger volumes of storage, particularly given the anticipated future growth in the archive market, which is why Sony and Panasonic decided to jointly develop this standard.
Both companies aim to launch initial systems with a (write-once) recording capacity of 300GB per double-sided disc, using crosstalk cancellation technology with a narrow track pitch, from summer 2015. The crosstalk cancellation technology electrically removes crosstalk from the adjacent tracks that increase as the track pitch becomes narrower, to achieve high-quality playback performance.
They have also laid out a roadmap for using their respective technologies to further expand the recording capacity per disc to 500GB and 1TB. The move to 500GB will require the use of high-order Partial Response Maximum Likelihood signal processing technology (which improves reproduction performance by allowing inter-symbol interference cancellation) to improve playback signal quality. Multi-level recording technology will be added for the move to 1TB capacity.
The companies said that “in recent times, demand for archival capabilities has increased significantly in the film industry, as well as in cloud data centres that handle big data, where advances in network services have caused data volumes to soar,” although one wonders that if cloud archival services take off whether there will still be a demand for Archival Discs when they do arrive. However, being able to access a physical disc on a shelf is still a reassurance to many, and will offer a further backup if the broadband connection is down, or the cloud service fails.
Sony already has a file-based optical disc archive system based on the optical disc technology it uses for its XDCAM products. This houses twelve optical discs within a compact cartridge to offer high-capacity storage. Each disc within the cartridge holds 25GB, offering a total range of storage capacities from 300GB to 1.5TB.
Panasonic also has its LB-DM9 series of optical disc storage devices, which uses a dedicated magazine, 20.8mm thick, to house twelve 100GB optical discs. A maximum of 90 magazines can be stored, providing a total storage capacity of 180TB. In addition, Panasonic adopted a newly-developed changer system together with RAID technology to offer rapid data transfer performance of up to 216MBps, while also ensuring high reliability by protecting data from unforeseen faults.
By David Fox