A lot of people have been asking about the archival properties of optical media. The National Institute of Standards and Technology has has a document titled Care and Handling of CDs and DVDs —A Guide for Librarians and Archivists with a great deal of information and recommendations on this subject.
This NIST Special Publication 500-252 is available online: http://www.itl.nist.gov/div895/carefordisc/index.html and also contains some basic technology information.
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