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.Three years ago I repeated the mind-numbing process of feeding 45 disks through the reader and verifying their checksums. Two years ago I did it again, 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: 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 18 years old, and from DVD-Rs nearly 16 years old. Your mileage may vary. Tune in again next year for another episode.
During the year I found a NetBSD1.2 CD dating from October 1996. It has checksums generated by cksum(1), all of which verified correctly despite a few read errors. So that CD is delivering good data after more than a quarter-century.