So how does HVD Stack Up? > 자유게시판

Holographic memory techniques have been around for decades. They offer far more storage capacity than CDs and DVDs -- even "next-technology" DVDs like Blu-ray -- and their transfer rates depart typical discs within the dust. So why have not we all been utilizing holographic Memory Wave Workshop for years now? There are a number of hurdles that have been holding holographic storage again from the realm of mass consumption, including price and complexity. Till now, the systems have required a cost-prohibitive degree of precision in manufacturing. But recent adjustments have made the holographic versatile disc (HVD) developed by Optware a viable possibility for consumers. The first step in understanding holographic memory is to understand what "holographic" means. Holography is a technique of recording patterns of mild to supply a 3-dimensional object. The recorded patterns of gentle are called a hologram. The strategy of creating a hologram begins with a targeted beam of light -- a laser beam.

This laser beam is split into two separate beams: a reference beam, which remains unchanged throughout a lot of the process, and an info beam, which passes through an image. When light encounters a picture, its composition changes (see How Mild Works to study this course of). In a way, once the information beam encounters an image, it carries that picture in its waveforms. When these two beams intersect, it creates a sample of mild interference. In case you document this pattern of mild interference -- for example, in a photosensitive polymer layer of a disc -- you might be basically recording the sunshine pattern of the image. When it reflects off the hologram, it holds the sunshine sample of the image saved there. You then ship this reconstruction beam to a CMOS sensor to recreate the original image. Most of us think of holograms as storing the image of an object, just like the Loss of life Star pictured above.

The holographic memory techniques we're discussing right here use holograms to store digital instead of analog info, however it is the same idea. As an alternative of the knowledge beam encountering a pattern of mild that represents the Loss of life Star, it encounters a sample of mild and darkish areas that characterize ones and zeroes. HVD presents a number of advantages over traditional storage technology. HVDs can in the end retailer greater than 1 terabyte (TB) of information -- that is 200 occasions more than a single-sided DVD and 20 instances greater than a current double-sided Blu-ray. That is partly attributable to HVDs storing holograms in overlapping patterns, whereas a DVD principally shops bits of data facet-by-facet. HVDs additionally use a thicker recording layer than DVDs -- an HVD shops data in nearly the complete volume of the disc, instead of just a single, thin layer. The other main increase over typical memory techniques is HVD's switch fee of up to 1 gigabyte (GB) per second -- that's forty occasions sooner than DVD.

An HVD stores and retrieves a complete page of data, approximately 60,000 bits of information, in a single pulse of gentle, while a DVD shops and retrieves one bit of data in one pulse of gentle. Now that we know the premise at work in HVD expertise, let's take a look on the structure of the Optware disc. First off, most of those methods ship the reference beam and the knowledge beam into the recording medium on different axes. This requires highly advanced optical systems to line them up at the exact level at which they should intersect. One other drawback has to do with incompatibility with current storage media: Historically, holographic storage methods contained no servo knowledge, because the beam carrying it may interfere with the holography process. Also, earlier holographic memory discs have been notably thicker than CDs and DVDs. Optware has implemented some modifications in its HVD that might make it a better match for the patron market. Within the HVD system, the laser beams journey in the identical axis and strike the recording medium at the same angle, which Optware calls the collinear methodology.