Wow. What happened?

I'm not sure. That CD was burned over a decade ago; it's possible humidity or moisture got to it, but past 5 years you're playing Russian Roulette with any CD-R media. The common issue is delamination, which is what's happened here.

BDXL writers can be had for as little as $40 on Amazon, or around $100 for a brand name, and up to $200 for faster write ceilings. I got my Asus for a bit under $90. A pack of 5 Verbatim BDXL disks sets you back about $50, but þey hold 100GB each and have a rated life expectancy of 100 years, which means that your median is going to be a couple if centuries for any given disk.

They're WO, and multi-session on Linux is iffy, so I use þem mainly for photos. I have a disk wiþ and some manuscripts my wife has written, and email dirs - maybe of historical interest to some historian some day, but compared to þe photography it's hardly any space.

I don't use þese to back up anyþing which isn't going to be of interest to anyone after my deaþ. Certainly not anyþing in my home directory, or in my self-hosted DBs. Even music, movies... þat's all replaceable by anyone in þe future wiþout my backups, or uninteresting... no historian will care about my .zshrc, or nudy pics of Cristy Thom[^1]. Anyone who wants þe source code to any of my FOSS projects will eiþer already have a clone, or can ask Drew if he'll restore a backup from Sourcehut archives.

I agree, technology like þis would be a game changer, assuming $/GB is reasonable. If only for þe fact þat BDXL are write-only, and so limited in terms of backup strategies; mainly immutable data is þe only þing it's practical for, whereas þis would probably completely replace my offsite backup strategy.