how good is the data reliability with CD ROM and DVD RAM?

On Sun, 22 Jul 2018, Warner Losh via cctalk wrote: Iff deliberately processed for archival permanence, metallic silver is long lasting. But, there have always been a lot of shortcuts taken to save time or money. A LOT of photographic materials were not adequately fixed ("hypo"/Sodium Thiosulfate?), and/or not adequately washed and or neutralizing the fixer. Archivala permanence calls for a fixer neutralizer, not just washing. For example, the Polaroid 55-P/N (4x5 print plus negative) had a different exposure index for the negative and the print, so one or the other would be off on exposure. The negative desperately needed to be more thoroughly fixed and washed, or it didn't last at all. Similarly with "stabilization" black and white prints. (anybody want an extra large stabilization processor? home lab movie film processing equipment?) There were many variations in the paper itself for photo prints. Some lasted better than others. Kodak has discontinued manufacturing of B&W photo paper, but there are a few other manufacturers still around. Color was done with dies, rather than metallic silver, and those fade. Remember how OVERLY bright Kodachrome was? Ektachrome held up a bit better. Longevity of digital data is predicated on periodic re-copying, and periodic transfer to other and newer media. "Cloud" is tempting, but the internet is written in sand; do you know ehre your data is? -- Grumpy Ol' Fred cisin at xenosoft.com