This is a great point about how pernicious corruption is: it replicates. Detection is more important than correction, at least you can stop the corruption from

This is a great point about how pernicious corruption is: it replicates. Detection is more important than correction, at least you can stop the corruption from spreading. It's typical for people to reuse storage hardware, and each derivative inherits prior corruption as well as contributing its own. Most people don't keep a long term unchanging archive, and even that archive likely has no means of unambiguous verification of data integrity.