C
urrent data storage platforms no doubt look like
sci-fi to someone who existed a mere 50 years
ago. Although magnetic storage which exists in
things like tape and hard drives has been around
since the early days of computing, someone who
stepped out of a time-warp from the fifties would
no doubt not know what to make of things like CDs and
DVDs, as well as data stored in little chips (flash storage).
Although these are by far the dominant storage technologies at present, it’s obviously very difficult to predict how
storage will evolve and develop in the future. With this in
mind, let’s take a look at some of the technologies which
may (or may not) exist in the years to come.
Holograms
Like CDs and DVDs, holograms are a form of optical storage. However, where CDs and DVDs store their information
in two dimensions, holographic storage ups this by taking
storage into the third dimension. Data can thus be stored at
multiple depths, greatly increasing the storage density. It’s
also faster. Because the discs in a conventional drive are
spinning, data is read in a linear fashion. In holographic systems, the data is read in parallel, resulting in much higher
data transfer rates.
To store the data, a laser beam is split into two beams, a
signal beam and a reference beam. The signal beam passes through a liquid crystal display, which shows a page of
binary information, as clear and black boxes.
The beam then travels into a light sensitive polymer or
crystal substrate, carrying the information from the LCD. A
second beam, called the reference beam, is guided onto a
separate path into the light-sensitive substrate, and where
the two beams meet, an interference pattern is created,
which is stored as a hologram.
To read the data back, the two beams are shone into the
substrate at exactly the same angle as was used to create
the data, and the hologram is then read by a Charged Couple Device (CCD), similar to that found in a digital camera.
By varying the angle of the beams, data can be stored,
potentially, in thousands of different layers, depending on
the quality of the substrate used.
The most likely application of such technology is for
long-term storage. Holograms lend themselves to stability
and reliability, which is a compelling advantage for deep
archiving purposes. Spinning hard drives and tape cannot
assure reliability out to 50 years or longer, whereas holographic discs tend to be fairly impervious to the elements.
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