I posted the same comment yesterday and for some reason got downvoted to oblivion.
Probably because of the "90% bit error rate" part of the comment. Obviously SSDs can't tolerate anything close to 90% bit errors.
If that kind of error rate could be corrected in the general case, it would have profound implications for information theory in general, not just hard drive manufacturing. It would be equivalent to a data compression algorithm that could crunch anything by 90%.
Basically the only way this could work would be if the SSD's actual physical capacity were several times larger than specified, so that the vast majority of its space could be used for redundant encoding. I'm sure that's true to some extent, but I doubt a 100 GB drive is actually a 1 TB drive with 90% redundancy.
Based on publications from SSD controller vendors, it looks like current 3D TLC NAND has raw bit error rates on the order of 10^-3 or better when it's healthy. Raw bit error rates in the 1-2% range correspond to a drive that's either worn out its write endurance, or has been sitting on a shelf in high temperatures for years and has some data retention issues. It looks like most SSD controllers are designed to maintain some degree of usability with ~1% raw bit error rates (albeit with performance penalties), but 2% RBER is pushing the limits of even the last-resort layer of ECC.
Your logic is flawed and/or the statement misleading.
While storing more than a single bit with bit error rate >= 50% does require at least some error modeling, it does not mean profound implications on information theory¹.
Yes, normal SSDs would not have raw bit error rate anywhere near 90%. Still, I recall tales of flash media approaching raw 90% error rate - mostly shitty SD cards making use of the not-completely-trashed sectors of scrap high-capacity chips with heaps of ECC.
¹ unless you really do mean general (theoretical) 90% error correction, which would indeed imply things such as P = NP and P != NP, yet it cannot be applied as an argument on specific real-world errors.
Anyway it’s irrelevant because to the filesystem the SSD is supposed to look like it does not in fact have all these errors. ZFS doesn’t really care about the storage format apart from perhaps supporting TRIM.
Probably because of the "90% bit error rate" part of the comment. Obviously SSDs can't tolerate anything close to 90% bit errors.
If that kind of error rate could be corrected in the general case, it would have profound implications for information theory in general, not just hard drive manufacturing. It would be equivalent to a data compression algorithm that could crunch anything by 90%.
Basically the only way this could work would be if the SSD's actual physical capacity were several times larger than specified, so that the vast majority of its space could be used for redundant encoding. I'm sure that's true to some extent, but I doubt a 100 GB drive is actually a 1 TB drive with 90% redundancy.