10-04-2017, 08:13 PM
Optical data storage is an alternative to magnetic disk data storage. At present, data access times are extremely slow for magnetic disks when compared to the execution speed of CPUs, so that any improvement in data access speeds will greatly increase the capabilities of computers, Especially with large data and multimedia files. Optical memory is a technology that uses a three-dimensional means to store data and can access such data one page at a time instead of sequentially, which leads to increases in storage density and access speed. Optical data storage systems are very close to being economically feasible. Photo-refracting crystals and photopolymers have been successfully used in optical data storage systems.
Such systems exploit the optical properties of these photosensitive materials together with the behavior of laser light when used to record an image of an object. Optical memory is located between the magnetic disk of the main memory with regard to data access times, data transfer rates, data storage density. As processors and buses almost double their data capacity Every three years (Moore's law) breach. CPUs can perform an instruction execution every nanosecond, which is six orders of magnitude faster than a single magnetic disk access. As the computer evolves, so do the applications for which computers are used. Recently, large binary files containing sound or image data have become commonplace, greatly increasing the need for high-capacity data storage and data access. A new form of high data storage capacity must be developed to handle these large files quickly and efficiently. Optical memory uses the basic principles of holography for recording purposes and therefore is also called as holographic memory system.
Optical memory is a promising technology for data storage, as it is a real three-dimensional storage system, you can access the data one page at a time instead of sequentially, and there are very few moving parts to minimize the limitations Of the mechanical movement. Optical memory uses a photosensitive material to record interference patterns from a reference beam and a coherent light beam, where the signal beam is reflected off an object or contains data in the form of light and dark areas. The nature of the photosensitive material is such that the recorded interference pattern can be reproduced by applying a light beam to the material which is identical to the reference beam. The resulting light which is transmitted through the medium will take the recorded interference pattern and will be collected in an array of laser detectors covering the entire surface of the holographic medium. Many holograms can be recorded in the same space by changing the angle or wavelength of the incident light. An entire page of data is accessed in this way.
Today, optical memory techniques are very close to being technologically and economically viable. The main obstacles to the implementation of optical data storage are recording speed, pixel size, laser output power, holograms degradation during access, temporary disintegration of holograms, and sensitivity of Recording materials. At an estimated cost of between $ 161 and $ 236 for a complete optical memory system, this can become a feasible alternative to the magnetic disk in the near future.
Optical media is ideal for storing sensitive information because it can be removed and secured. Data Play technology takes advantage of this; The encrypted keys are stored in the support itself, the contents are encrypted separately and accessed through the key exchange. .