Friday, May 23

3D Optical Data Storage


Introduction

                3D Optical Data Storage is the term given to any form of opticaldata storage in which information can be recorded and/or read with three dimensionalresolution (as opposed to the two dimensional resolution afforded, for example, by CD). This innovation has the potential to provide petabyte-level mass storage on DVD-sized disks. Data recording and readback are achieved by focusing lasers within the medium. However, because of the volumetric nature of the data structure, the laser light must travel through other data points before it reaches the point where reading or recording is desired. Therefore, some kind of nonlinearity is required to ensure that these other data points do not interfere with the addressing of the desired point.

Drive Design

        A drive designed to read and write to 3D optical data storage media may have a lot in common with CD/DVD drives, particularly if the form factor and data structure of the media is similar to that of CD or DVD. However, there are a number of notable differences that must be taken into account when designing such a drive.


Destructive Reading

         Since both the reading and the writing of data are carried out with laser beams, there is a potential for the reading process to cause a small amount of writing. In this case, the repeated reading of data may eventually serve to erase it (this also happens in phase change materials used in some DVDs).

Commercial Development

        In addition to the academic research, several companies have been set up to commercialize 3D optical data storage and some large corporations have also shown an interest in the technology. However, it is not yet clear how the technology will perform in the market in the presence of competition from other quarters such as hard drives, flash storage, and holographic storage.

Data Recording During Manufacturing

        Data may also be created in the manufacturing of the media, as is the case with most optical disc formats for commercial data distribution. In this case, the user cannot write to the disc - it is a ROM format. Data may be written by a nonlinear optical method, but in this case the use of very high power lasers is acceptable so media sensitivity becomes less of an issue.

Comparison With Blu-Ray Disc


        Blu-ray Disc (official abbreviation BD) is an optical discstorage medium designed to supersede the DVD format. The disc diameter is 120 mm and disc thickness 1.2 mm plastic optical disc, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB (23.31 GiB) per layer, with dual layer discs (50 GB) being the norm for feature-length video discs. Triple layer discs (100 GB) and quadruple layers (128 GB) are available for BD-XL Blu-ray re-writer drives.


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