Some time ago I found a bunch of optical discs with backups I burned in 2006-2008. Out of curiosity I've decided to read them to get some intuition how well data was preserved. Note that this is not a scientific study, it's a purely anecdotal data—still, I found it interesting.
The discs were lying in a cardboard box unopened for, I guess, at least five years and three moves. No sleeves, no other kind of protection; just the box itself, with discs being at the bottom of the box and lots of other stuff covering them. Some clearly visible scratches and other type of dust, which I took care of by wiping with a dry piece of cloth. I took my USB LiteOn DVD reader and run dvdisaster over all the discs. While this tool has some special raw reading mode for CDs, it was nothing more than a repeated dd for DVDs, so I don't think it mattered much. All discs were full or almost full.
First impression—these things are so slow. I haven't been using optical media for a long time now and while I expected that, well, this is a pretty outdated technology after all, it was still slower than what I remembered. The results:
- Platinum 8x DVD+R: everything ok in the first pass,
- TDK 16x DVD+R: everything ok in the first pass,
- TDK 16x DVD+R: first pass: ~95% of data recovered, outer tracks look damaged; after few days of repeated reads, everything recovered,
- Msonic 52x CD-R: everything ok in the first pass,
- Fujifilm 16x DVD+R: everything ok in the first pass,
- Esperanza 56x CD-R: everything ok in the first pass,
- Emtec 16x DVD-R: everything ok in the first pass,
- TDK 16x DVD+R: everything ok in the first pass.
In the end, everything turned out fine except for this one disc that was a bit of a problem. I recall that I was buying the cheapest available brands at the time, yet the results were much better than I expected.
Again, this is purely anecdotal evidence, though I guess it does inspire a bit of confidence in optical media. For "small" amounts of data it's quite viable long-term storage without even going into the archival-grade media.
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