I’ve replaced the aging Blu-ray drive in my computer with a shiny new LG one. Amongst other things, this one burns Blu-ray discs rather than merely reading them. And, I see from the LG website, it also supports the new 128GB BDXL format.
But on the front was something I’d never heard of: M-Disc. A little googling around revealed that this is a new write-once recordable DVD technology that involves making actual pits in the recordable material, rather than simply changing the reflectivity of dies. The advantage is longevity. They say that these are good for a thousand years and impervious to UV, light and temperature (within reason I imagine). They are 4.7GB capacity.
It seems that you need a special drive to burn them, but once burnt they are compatible with all DVD drives.
Wikipedia says that a Blu-ray version is on the way.
I see that the M-Disc people are selling blank discs from their website. Surprisingly, and pleasingly, they are not insanely expensive: $30 for a pack of ten. Pretty good value if they really are good for a thousand years.