The only write once media I'm aware of that is in significant use are WORM tapes. They don't offer significant advantages over regular tapes, but for compliance reasons it can be useful to just make it impossible to modify the backups.
You mean the UV erasable kind? Essentially phase change memory? Very hard to miniaturize?
Because the older Flash aren't as stable when miniaturized as you'd expect. Current flash is a direct descendant of these, they only are more stable because the cells are much chunkier and thus with lower leakage.
I was thinking of the anti-fuse based PROMs not EPROMs sorry. I figure if you miniatures those they'd be faster and denser and use-based fully reliable.
I thought along that route as well but I'm not sure how the feature scale of a fuse compares to the size of a flash cell - especially since the latter can contain multiple bits worth of info (MLC). Assuming the fuse write results in a serious physical state change of some sort, I suspect that the energy required for high speed writes (at SSD speeds) may become substantial.
That being said, it's not clear how innovation has occurred in this direction in the storage space.
