During a recent Rust Q&A Session on my twitch channel, someone asked a question that seemed simple: why are small string types, like SmartString or SmolStr, the same size as String, but small vec types, like SmallVec, are larger than Vec?

Now I know I just used the adjective simple, but the truth of the matter is: to understand the question, we're going to need a little bit of background.

Everybody knows how to use files. You just open up File Explorer, the Finder, or a File Manager, and bam - it's chock-full of files. There's folders and files as far as the eye can see. It's a genuine filapalooza. I have never once heard someone complain there were not enough files on their computer.

But what is a file, really? And what does reading a file entail, exactly?