What`s the Lifespan of Optical Discs?
I read the April issue of InfoStor and have a follow-up question that you may be able to address. Does anyone have real data describing the storage lifetimes of these media: magnetic tape, CDROM, CD-R, CD-RW, DVD, DVD+RW, DVD-RAM?
A lot of hearsay and casual numbers abound in the published literature: for example, 40 years for optical discs, as cited in your article "Optical Options Expand" [April, p. 43], vs. 100+ years cited commonly over the past several years, vs. an article in Business Week (April 20) and Edupage (April 16), which quoted a RAND researcher as saying it`s more like 5 to 10 years for CD-ROM media.
I (and others at my company) are interested in knowing the real scoop. Who is researching failure modes of these media? What are the standards being used? Who is doing testing, and how are they doing it?
Many individuals, companies and governments are expending huge amounts of time and energy in storing data on these media.
Tim J. Voss
Lawrence Livermore National Laboratory
Two good sources for optical-related questions are the Optical Storage Technology Association (www.osta.com) and Freeman Associates (www.freemaninc.com), a market research firm in Santa Barbara, CA. According to Freeman`s "Optical Storage Outlook" report, the recorded data life of rewritable optical media such as magneto-optical is generally 10 to 50 years (although exceptions exist). For CD-RW and DVD-RAM, it`s generally 10 to 30 years.
But Bob Abraham, vice president at Freeman, offers the following caveat: "We don`t publish all specifications, in part because certain specs are very subjective, or are applicable for differing ambient conditions from supplier to suppler, or are subject to gamesmanship. I encourage you to be careful when you receive life specs from manufacturers and to be certain that comparisons are on an apples-to-apples basis."
Maybe some of our readers can help you with information on who`s doing real-life testing and the methods they`re using?