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CNN.com -CDs, DVDs not so immortal -May 6, 2004 <br />1 <br />Page 2 of 3 <br />to cause skipping, while scratches on the top can easily penetrate to the aluminum layer. Even the <br />pressure of a pen on the label side can dent the aluminum, rendering the CD unreadable. <br />Koster has taken to copying his CDs on his computer to extend the life of the recordings. <br />Unfortunately, it's not easy to figure out how long those recordable CDs will work. <br />Fred Byers, an information technology specialist at the National Institute of Standards and <br />Technology, has looked at writeable CDs on behalf of government agencies, including the <br />Library of Congress, that need to know how long their discs will last. <br />Manufacturers cite lifespans up to 100 years, but without a standardized test, it's very hard to <br />evaluate their claims, Byers says. The worst part is that manufacturers frequently change the <br />materials and manufacturing methods without notifying users. <br />"When you go to a store and buy a DVD -R, and this goes for CD -R as well, you really don't <br />know what you're getting," he says. "If you buy a particular brand of disc, and then get the same <br />disc and brand six months later, it can be very different." <br />This renders the frequently heard advice to buy name -brand discs for maximum longevity fairly <br />moot, he says. <br />DVDs are a bit tougher than CDs in the sense that the data layer (or layers -- some discs have <br />two) is sandwiched in the middle of the disc between two layers of plastic. But this structure <br />causes problems of its own, especially in early DVDs. The glue that holds the layers together can <br />lose its grip, making the disc unreadable at least in parts. <br />Users that bend a DVD to remove it from a hard - gripping case are practically begging for this <br />problem, because flexing the disc puts strain on the glue. <br />Rewriteable CDs and DVDs, as opposed to write -once discs, should not be used for long -term <br />storage because they contain a heat - sensitive layer that decays much faster than the metal layers <br />of other discs. <br />For maximum longevity, discs should be stored vertically and only be handled by the edges. <br />Don't stick labels on them, and in the case of write -once CDs, don't write on them with anything <br />but soft water -based or alcohol -based markers. <br />Also, like wine, discs should be stored in a cool, dry place. Koster's friend Mark Irons, of <br />Corvallis, Ore., stored his CD collection in a cabin heated by a wood - burning stove. The <br />temperature would range between 40 degrees and 70 degrees in the space of a few hours. Now, <br />the data layer of some of his CDs looks as if it's being eaten from the outside. <br />Irons is still pretty happy with CD technology, since it beats vinyl LPs and tape for longevity. <br />Now that he's moved his discs to an apartment with a more stable temperature, he's noticed that <br />the decay has slowed. <br />"I'm hoping they'll hold out till that next medium gets popular, and everyone gets to buy <br />everything over again," he says. <br />http : / /cnn. technology.printthis. clickability. com/pt /cpt ?action =cpt &title =CNN. com + - +C... 5/6/2004 <br />