Surprisingly, I'm getting good data from CD-Rs more than 14 years old, and from DVD-Rs nearly 12 years old. Your mileage may vary.Four years ago I repeated the mind-numbing process of feeding 45 disks through the reader and verifying their checksums. Three years ago I did it again, and then again two years ago, and then again a year ago.
It is time again for this annual chore, and yet again this year every single MD5 was successfully verified. Below the fold, the details.
| Month | Media | Good | Bad | Vendor |
| 01/04 | CD-R | 5x | 0 | GQ |
| 05/04 | CD-R | 5x | 0 | Memorex |
| 02/06 | CD-R | 5x | 0 | GQ |
| 11/06 | DVD-R | 5x | 0 | GQ |
| 12/06 | DVD-R | 1x | 0 | GQ |
| 01/07 | DVD-R | 4x | 0 | GQ |
| 04/07 | DVD-R | 3x | 0 | GQ |
| 05/07 | DVD-R | 2x | 0 | GQ |
| 07/11 | DVD-R | 4x | 0 | Verbatim |
| 08/11 | DVD-R | 1x | 0 | Verbatim |
| 05/12 | DVD+R | 2x | 0 | Verbatim |
| 06/12 | DVD+R | 3x | 0 | Verbatim |
| 04/13 | DVD+R | 2x | 0 | Optimum |
| 05/13 | DVD+R | 3x | 0 | Optimum |
- Month: The date marked on the media in Sharpie, and verified via the on-disk metadata.
- Media: The type of media.
- Good: The number of media with this type and date for which all MD5 checksums were correctly verified.
- Bad: The number of media with this type and date for which any file failed MD5 verification.
- Vendor: the vendor name on the media
Surprisingly, with no special storage precautions, generic low-cost media, and consumer drives, I'm getting good data from CD-Rs more than 19 years old, and from DVD-Rs nearly 17 years old. Your mileage may vary. Tune in again next year for another episode.
Last year I found a NetBSD1.2 CD dating from October 1996 whose cksum(1) checksums all verified correctly despite a few read errors. That CD was still delivering good data after nearly 26 years, but this year a couple of the checksums failed.
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