Monday, September 05, 2005

Are DVDs and CDs Disintegrating?

A study, reported in "Stability Comparison of Recordable Optical Discs—A Study of Error Rates in Harsh Conditions," researched how writable CD and DVD media from various manufacturers fared in extreme temperatures and when exposed to harsh light and extremely humid conditions for prolonged periods of time. Researchers attempted to accelerate the media aging process and see how well they and the data written to them held up. Their findings show that dyes matter, integrating gold and silver can help, light can hurt as can humidity, and the quality of the media makes a difference.I think the study is valuable as a starting point for optical-media care, but it's clear that the implication for consumers is that something must be done now to protect their CD and DVD data. Thankfully, "scratch-proof" optical media are appearing all over the place. And a new product called Archival Gold, from Delkin, uses gold and silver in the reflective layer, which has been shown to help with data verity. An ad from Delkin promises that it's "the most reliable CD-R" on the planet. The company even combined its gold standard with the NIST's recommended dye, phthalocyanine. A pack of 100 discs costs $139. That's considerably more expensive than comparable optical media from Maxwell or Verbatim. Capitalizing on the report's findings is a savvy business move and, to be fair, media using gold in the reflective layer and the special dye have beReliability is a very amorphous proposition in the world of optical media. No one knows how long such media will last, and the same NIST report says: It is demonstrated here that CD-R and DVD-R media can be very stable. . . Results suggest that these media types will ensure data is available for several tens of years and therefore may be suitable for archival uses. It's reasonable to translate "tens of years" into 100 years or more. And, again, the error rates the NIST saw were found in conditions "not representative of discs stored in typical, normal, or ideal storage conditions." A clear jewel case sitting on a shelf on top of the TV or DVD player would likely classify as "normal." Here are some guidelines for the ideal treatment and storage of media:
(1) Use proper storage or jewel cases. If you want to be a little obsessive about it, use colored ones, to block out potentially harmful light.
(2) Handle discs by placing your thumb through the center and your fingers around the outer edge.
(3) Clean discs with a moist cloth and dry them with one that is dust-free. When cleaning and drying, drag the cloths from the inner to the outer edge of the disc. Never use a circular motion.
(4) Mark with a soft marker or a label (on the nonread side). Avoid using pens, pencils, or any sharp objects on the disc.
(5) Protect both sides. A scratch on the label side can be even more damaging than one on the read side.
These instructions are not difficult. They're common sense, and whether or not you're using gold, silver, and just the right dye, these should help your burned media last for decades to come.
One last thought: Though I cannot dismiss the scratch-proof methods used by vendors, I have to believe that these extreme measures probably wouldn't be necessary if folks followed these simple guidelines.


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