A filesystem is an abstraction built on a block device. A block device just gives you a massive array of bytes and lets you read/write from them in blocks (e.g.

A filesystem is an abstraction built on a block device. A block device just gives you a massive array of bytes and lets you read/write from them in blocks (e.g. write these 300 bytes at position 273041). A block device itself is an abstraction built on real hardware. "Write these 300 bytes" really means something like "move needle on platter 2 to position 6... etc" S3 is just a different abstraction that is also built on raw storage somehow. It's a strictly flat key-object store. That's it. I don't know why people have a problem with this. If you need "filesystem stuff" then implement it in your app, or use a filesystem. You only need to append? Use a database to keep track of the chain of appends and store the chunks in S3. Doesn't work for you? Use something else. Need to "copy"? Make a new reference to the same object in your db. Doesn't work for you? Use something else. S3 works for a lot of people. Stop trying to make it something else. And stop trying to change the meaning of super well-established names in your field. A filesystem is described in text books everywhere. S3 is not a filesystem and never claimed to be one. Oh and please study a bit of operating system design. Just a little bit. It really helps and is great fun too.