GristyMcFisty reports that
researchers at Imperial College London, UK, are investigating a new optical disc
which could hold up to 1
terabyte of data. Yes, that's right, 1 terabyte, meaning 1,000 gigabytes of
data. The disc would have four layers of 250GB each.
Sounds great but don't expect to find these new
discs in your local shop anytime soon. If sufficient funding can be found, the
researchers say a commercial version of disc won't be available until
2010. And besides that, a consumer writing device hasn't even been investigated
yet:
Information is encoded on a normal DVD in
the form of microscopic indents on the surface of the disk. The presence
or absence of an indent corresponds to a binary piece of information - a
'1' or a '0'. Indents are detected by beaming light onto a disk with a
laser and measuring the amount of light that bounces back.
Using tracks embedded at several depths
within a disk, it is possible to store more data on the highest capacity
disks. Multilayer DVDs hold about 16 gigabytes of data, which equals about
8 hours of high quality video.
But the researchers realised that the
polarity of light might also be used to encode information. They developed
a type of disk that incorporates angled ridges within the pits in order to
subtly alter the polarity of the light that gets reflected. This can be
used to store 10 times' more data than is currently possible, they
say.
All-in-one
disk
Using the technique, the researchers
think it should be possible to create disks capable of holding 250
gigabytes in a single layer. This is enough to store 118 hours of video,
which could allow every episode of long-running television shows to be put
on one disk. Using a four-layer disk would mean a terabyte could be
stored.
In the new system, light polarised in a
single direction is beamed onto the surface of the disk. Some bounces back
with a polarity at 90 degrees to that of the original beam. By measuring
how much light comes back in each of the two directions, it is possible to
work out the precise angle of the slope.
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Source: NewScientist.com
