|The British Caving Association
|Data Longevity on CD-ROMs
|Page 1 of 1|
|Author:||David Gibson [ Thu 04 Jul 2013 15:41 ]|
|Post subject:||Data Longevity on CD-ROMs|
I have been asking the following question for at least three years now. Nobody seems to have an answer although, no doubt, a very diligent trawl of the web would would come up with something. I notice that over on ukcaving.com Martin Sluka has just posted an interesting URL, http://www.datatresordisc.eu/introduction-page-dtd.html, which may be what Im looking for.
My question, (which also appears at http://uclue.com/?xq=5655) is...
I need to reliably archive data onto CD-ROMs (or other optical media if that would be better). Where can I purchase suitable CDs, a writer and software? I need the media and equipment to be guaranteed in quality, e.g. by ISO 9000 traceability and not just a recommendation that "CDs from WallMart are usually good" . Also, the items need to be readily available in the UK. My guess is that there must be companies that provide archive-quality goods and that there must be people using them - e.g. libraries.
BACKGROUND: An article in New Scientist included the following table of data lifetimes. (The online article at http://www.newscientist.com/article/mg2 ... ledge.html does not include the table, which was part of a graphic and not textual).
20 years: Analogue tape
14 years: Digital tape
16 years: Audio CD, DVD movie
07 years: CD-R (cyanine and azo dyes)
07 years: CD-RW, DVD-RW, DVD+RW
16 years: CD-R (phthalocyanine dye, silver metal layer)
100 years: CD-R (phthalocyanine dye, gold metal layer)
16 years: DVD-R, DVD+R
10 years: Flash
The CD-ROMs that one buys at a retail outlet do not say what they are made of so I need to know a) where to get the required phthalocyanine/gold CDs and b) how to guarantee that they are what they purport to be.
On that last point, I note from http://en.wikipedia.org/wiki/CD-R that "Unfortunately, many manufacturers have added additional coloring to disguise their unstable cyanine CD-Rs in the past, so the formulation of a disc cannot be determined based purely on its color. Similarly, a gold reflective layer does not guarantee use of phthalocyanine dye". Hence my need for ISO 9000 certification. That Wikipedia article makes a number of other points, including one about the need for a good-quality CD writer. Therefore, I also need to know where to get a *verifiably* good CD writer.
SUMMARY: I am looking for the materials (discs, writer, software) with which to perform an archiving task, which are readily available in the UK, and with some guarantee that the CDs are going to survive for some years to come (based on documented manufacturer’s data, ISO 9000 traceability, etc.).
Some CDs that I burned just 7 or 8 years ago are already unreadable
|Page 1 of 1||All times are UTC [ DST ]|
|Powered by phpBB® Forum Software © phpBB Group