What ailes file systems
File systems have a single region of failure: the table. Corruption of allocation table renders all data waste. Such corruption reduces the problem of finding files in to the known problem of non trivial 'string comparison/search'. Go write a software to find the file headers in a DVD. We can write one but only if someone can lend a computer that can compute it before I am dead! So we need an idea that does away single region of failure.