[blagie]

No, it's not read-only. It's just that the writes are somewhat random, and in control of God and physics, rather than, of human design.

(speaking as someone with a big pile of CD-Rs in the attic, most of which have some forms of corruption on them)

I'd love to see a standard like M-Disc in mainstream use. The problem is optical has not kept up with magnetic. M-Disc is about $100 for 100GB. In contrast, I bought a 20TB HDD for ≈$200-300, so about $10/TB, so 100x cheaper. It's as cheap to buy a HDD every year and make a full copy for a century as it is to buy M-Disc.

I don't think that's fundamental, so much as economies-of-scale. Optical should be cheaper per density, more stable, and write-only, but CD was invented in 1982, DVD in the nineties, and we've only made limited progress since then. HDD were on a rapid growth curve until SSDs came in. Today, SSDs are on the growth curve, and I expect will eventually be cheaper than magnetic or optical.

[ufocia]

Optical made advancements beyond the DVD. However they caught on only in a limited manner. There is Blue-Ray, now 128GB 4-layer. However, due to the amount of data we generate and consume, long term storage is less of a concern at the consumer level, i.e. there is almost always more where that came from. Content has, simply put, been commoditized.

[blagie]

I never said they didn't, and indeed, cited 100GB optical media. I said they made _limited_ progress.

In 1982, a 20MB HDD was considered large, while a CD is 640MB. That's an almost insurmountable 20x advantage to optical.

By the late nineties, a DVD was 4.7GB, while typical HDDs were maybe 500MB-2GB, giving a more modest advantage to optical.

In 2024, a HDD is maybe 200 times bigger than optical (20TB versus 100GB), while an SSD is maybe 10x bigger (1TB versus 100GB).

Prices are also worth looking at. 100GB media is maybe $10/disk. I remember buying CD-Rs and DVD-Rs in stacks of 20-100, at maybe 10 cents-$2 per disk, depending on type, quantity, and year. The cost-per-byte for optical media has hardly changed in two decades.

So limited progress.

[RhysU]

> control of God and physics

If either God or physics want it, they already have root.