- Are DVDs and CDs Disintegrating?
One of my favorite things to do is to rent DVDs from my local video rental store. With my wife and kids, I'll watch two to three every weekend. Lately, the experience has been marred by what I call "Viewus Interruptus." This is the momentusually three-quarters of the way through the filmwhen the image freezes and then cascades into a blocky, unwatchable mess.
I have a number of strategies for getting around this (usually after we all cry out in unison, "Aww, geez!"). First, I'll try fast-forwarding through the bad patch. Next, I'll stop the film and return to the spots where things went bad, using the chapter/scene menu. Both plans usually fail, forcing me to remove the DVD from my player. What I find is often not pretty.
The read side of the disc is usually covered in grease, fingerprints, and other unidentifiable debris. (Often it appears as if someone had tried to make the DVD an integral part of a peanut butter and jelly sandwich.) I'll use a damp cloth to clean it and then dry it off with Scott toilet tissue. (Facial tissue leaves dust.) Once I've done all this, the DVD invariably plays without a problem.
I bring this up for a reason. If people are so incapable of taking care of a DVD they hold on to for, perhaps, a day, I wonder why anyone should expect them to know how to protect their own optical media?
Yet the very same consumers who drop, scratch, and generally mutilate their DVD rentals are also, it seems, the ones who were so frightened by a 2004 study by the Journal of Research of the National Institute of Standards and Technology (NIST). The studied concerned data verity of DVDs and CDs, as well as the longevity of media in general. And consumers are now ready to try all sorts of new, heavy-duty methods for protecting their optical media archival data.
The study, reported in "Stability Comparison of Recordable Optical DiscsA 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 realize this all sounds pretty dire, and the last item, especially, should not be news to my readers. But the report also adds:
It should be noted that results presented in this paper represent continuous exposure to direct light and extreme temperature/humidity levels. The error rates are not representative of discs stored in typical, normal or ideal storage conditions.
In fact, researchers admit that the report's data does not indicate how long optical media will really last. (A more in-depth study is currently under way to explore that question.)Continue reading...