> Chunks don't span files. Each file is validated by the hash of its merkle tree. This is the biggest user-visible change, since it means you can download one file without downloading others.
But can't you already download one file? I suppose if a chunk spans two files, you may get a few extra KB of another file you don't want, but it's not noticeable from a user perspective.
With a lot of clients you'll end up with bogus files on disk as the neighbours of the file you wanted - the client has to download the whole chunk and has to be able to validate its checksum, so it has to put it on disk somewhere. Not a huge problem, but annoying.
But can't you already download one file? I suppose if a chunk spans two files, you may get a few extra KB of another file you don't want, but it's not noticeable from a user perspective.