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Comment by namibj | Hacker News Reader

Beware that normal CD-R uses organic dye subject to rotting. Use either something like M-DISC or normal BD-R discs (HTL, with an anorganic phase-change recording layer).

I also suggest using at least dvdisaster (I suggest it's RS03 codec in augumented-image mode) or equivalent (if you come across a proper competitor to dvdisaster RS03, please let me know).

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I've heard about the rotting, we've got a plan in about a year or two to do a key ceremony to move stuff onto more permanent hardware we can retain for at least 20 years (our roots last 15)

What that hardware will be is still an open question, but probably BD-R HTL.

Also worth noting (I think it's in the script too from memory) we make at least 3 identical copies of each CD in case of CD failure.

Yeah, from my understanding the rot is literally a fungus/bacteria colony that eats the dye. If you store the 3 copies separately in sealed containers, regular (no worse than yearly) inspections should probably suffice. The damage is visible; if anything looks off, put it back and immediately organize preemptive data rescue. This can be obvious discoloration (likely with a gradient) or discrete specs, the latter can also happen to BD-R HTL where they are "just" delamination. That is thankfully a fairly slow progressive effect from AFAIK the acrylic glue slowly hydrolyzing, and can be counteracted by cold constant-temperature constant-low-humidity storage (an office cabinet with AC is better than a finished basement w/o AC).

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