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Techno Page Desktop holographic
data storage There is still some fine tuning that must be done before such a high-density storage device can be marketed, but researchers have suggested that they will have small HDSS devices ready as early as 2003. These early holographic data storage devices will have capacities of 125 GB and transfer rates of about 40 MB per second. Eventually, these devices could have storage capacities of 1 TB and data rates of more than 1 GB per second. They would be fast enough to transfer an entire DVD movie in 30 seconds. The technology works in such a way that, a blue-green argon laser is split into two beams by a beam splitter, which is bounced off one mirror and travels through a spatial-light modulator (SLM). An SLM is a liquid crystal display (LCD) that shows pages of raw binary data as 'clear' and 'dark' boxes. The binary information is carried by the signal beam around to a light-sensitive crystal. Some systems use a photopolymer in place of the crystal. The second beam, called the reference beam, shoots out the side of the beam splitter and takes a separate path to the crystal. When the two beams meet, the interference pattern that is created stores the data carried by the signal beam in a specific area in the crystal - the data is stored as a hologram. When the idea of an HDSS was first proposed, the components for constructing such a device were much larger and more expensive. For example, a laser for such a system in the 1960s would have been six feet long. Now, with the development of consumer electronics, a laser similar to those used in CD players could be used for the HDSS. LCDs weren't even developed until 1968, and the first ones were very expensive. Today, LCDs are much cheaper and more complex than they were 30 years ago. Almost the entire HDSS device can now be made from off-the-shelf components, which means that it could easily be mass-produced. Although the components are more freely available now than they were in the 1960s, there are still some technical problems that need to be worked out. For example, if too many pages are stored in one crystal, the strength of each hologram is diminished. If there are too many holograms stored on a crystal, and the reference laser used to retrieve a hologram is not shined at the precise angle, a hologram will pick up a lot of background from the other holograms stored around it. Researchers are confident that technologies will be developed in the next two or three years to meet these challenges. This DVD-like disc would have a capacity 27 times greater than the 4.7-GB DVDs available today, and the playing device would have data rates 25 times faster than today's fastest DVD players. Internet
Explorer 6 MSN Messenger users can dock their chat sessions within the browser, the way Netscape 6 docks AOL Instant Messenger. The Media bar integrates Windows Media Player into the browser, so you can listen to streaming audio without opening a separate application. IE 6 also has
some significant new privacy improvements. For the first time in
a browser, you can set an alarm and have IE 6 alert you to third-party
cookies that share your personal settings with other entities without
your consent (such cookies are usually associated with banner ads).
Further, you can build an Internet security profile using Internet
Options, which lets you do things like setting privacy preferences
from low to high, viewing site certificates, and receiving warnings
before sending non-encrypted data over the Web. E-mail: technopage_lk@yahoo.com |
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