Empty promises are putting your most important files at risk
CD/DVD experiential life expectancy is 2 to 5 years even though published life expectancies are often cited as 10 years, 25 years, or longer. However, a variety of factors discussed in the sources cited in FAQ 15, below, may result in a much shorter life span for CDs/DVDs. Life expectancies are statistically based; any specific medium may experience a critical failure before its life expectancy is reached. Additionally, the quality of your storage environment may increase or decrease the life expectancy of the media. We recommend testing your media at least every two years to assure your records are still readable.
From The U.S. National Archives and Records Administration Web site (Item 6 in the FAQs)
Who knew? Certainly I didn’t. For some time now, DVDR manufacturers have been leading us to believe that by replacing the silver reflective layer with gold, they have somehow increased the life-span of your data on their DVDR discs. Most of us really don’t have the time to dig into the technology behind optical storage media to know if that premise makes sense. The discs cost more, come with a claim of preserving your files for 80 to 100 years so what’s there to doubt?
Unfortunately, there are many things about DVDRs that can be considered weak points in the design. Any one of these weak points can easily and silently put your important files in jeopardy. Most notably:
- when silver was used as the reflective layer, it was prone to oxidizing which defeated its ability to reflect. This problem was solved for conventional disc design by replacing silver with gold.
- your data is stored on a layer of organic dye as it reacts to the laser beam when the disc is burned. This dye, being of an organic nature, breaks down even in the best of conditions. It is very susceptable to exposure to light and temperature.
- the beam used to burn the data onto the dye layer is also used to read the data back, causing additional degradation of the data layer every time the disc is read.
Recently, people have begun going to their DVDR archives to access their important files and are discovering this unexpected data loss. A writer for the New York Times told of his experience and people commented in droves about their experiences as well.
Feel free to share your experiences in the comments here.
Tags: archival media, archive, DVD, DVDR, DVDs, optical storage, photos, storage media, videos
Cranberry, Cranberry Venture Partners, Society, Technology | Joe Beaulaurier | 
October 22, 2009 7:29 am
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