Most, if not all, the studies of CD permanence have come out of the industry, where "archival" may be defined as 5 years or less -- likely the explanation for the claim that the current generation of disks meet archival requirements. With the exception of a gold-coated glass version (Centuiry Disk) that is relatively expensive and seldom used, there seems to be consensus that the life expectancy of CDs ranges from 5-20 years under "average" conditions. I can't point to a published research study, but the National Media Laboratory (POB 33015, St. Paul, MN 55133) is engaged in testing of related materials. The problem with CD as a long-term format is not so much the vulnerabilities of the physical object (although there are some -- moisture and surface sensitivity to pressure, as from a writing instrument appear to be among the worst) as the speed of technology change. If an institution commits to the medium, it must also commit to frequent hardware upgrades. I've seen at least one estimate of a 3-5 year cycle of technology change through the beginning of the 21st century. The institution must also commit itself to a systematic program of collections management including sampling, refreshment (copying within a format generation), and migration (copying from one generation to the next). If the institution is generating its own CDs, it must also maintain extensive records of programming, electronic architecture, and disk contents to permit long-term retrieval of disk contents. NEDCC has an excellent free handout on these consideration written by Paul Conway, head of Yale's preservation programs. If you'd like a copy, send your physical mail address to me with a request. _________________________________ Karen Motylewski 508-470-1010 Northeast Document Conservation Center 508-475-6021 fax 100 Brickstone Square <[log in to unmask]> Andover, MA 01810 Use KM in subject field