But I think of CDs as the start of this era of transience. Every single CD I burned was useless after a couple of years of sitting in a spindle. Most of my 3.5" floppies from the 90s still work fine, with maybe a few bad sectors. I don't know, maybe I bought cheap CDs to start with--I think the factory burned non-writable CDs lasted.
"Prerecorded" CDs are actually not "burned" by a laser (in the way that CD-Rs are) in the factory, but "stamped"/injection molded from a negative. It's a completely different process!
Since there is no photosensitive dye involved on the final prerecorded disc, this makes them orders of magnitude more durable. That dye is what breaks down over time on CD-Rs, making them unreadable.
Oh that's weird, I'm right now as I type this, listening to a CDDA disc I burned in 2009 and it's flawless. At least nothing's getting through the error correction; I suppose I could scan it and check the C1/C2 error rates, but I don't know what they were immediately post-burn to compare to. (I used to scribble the burn date on the front, so combined with the ATIP batch data, I could eventually build up empirical data about which ones failed prematurely. Never came up with enough failures to produce a signal from the noise, but I have all these discs with burn dates on them.)
DVDs were pretty much the opposite. I burned a lot of DVD coasters. Had even more that failed a few months into service. Dual-layer were so expensive for the good blanks, and so dismally unreliable for the cheap blanks, that I seldom bothered -- two mid-grade single-layer discs were cheaper and more reliable.
Floppies have been hit-or-miss for me, they're more susceptible to mildew if stored in a damp basement, and cleaning solutions are a you-get-one-shot affair since you have to cut open the jacket and remove the flexible media. But if kept dry, I've had decent (95%?) success rates from mid-80s-to-early-90s floppies. A drive cleaning disc is essential.
I've read 20 years old CD-Rs without any apparent trouble. Simple trick: do not burn at the highest possible speed. Easily found information at the time.
Do note that some media has a sweet spot recording speed - apparently (as I recently rediscovered in practice), DVD-Rs don't like to be burned too slowly neither.
>Most of my 3.5" floppies from the 90s still work fine, with maybe a few bad sectors.
I never experienced such durability of floppies. here 10% where DOA, and a disk which survived 3 years was a venerable older one. Maybe the warm, humid and dusty air in here?
My experience with 3.5” diskettes was too that they were unreliable- however the older 5.25” ones seemed a lot more durable. I suspect it has to do with the fact that by the end of their market-life 3.5” had to be made super cheap as nobody considered 1.44mb big enough in the late 90s and thus the quality of late-production floppies was low due to cost cutting.
3.5" floppies I think had a certain time-span (1980s - mid 1990s? maybe) when they were mostly good. Also double density disks always felt more reliable to me.
