There's a long history of mocking and decrying the file as a user-level concept, and many applications hide the concept from the user, even though they store us

There's a long history of mocking and decrying the file as a user-level concept, and many applications hide the concept from the user, even though they store user data in the filesystem. Music players (such as iTunes) are an example: there are songs, albums, and artists, but files do not show up in the UI in any way. This is standard practice at the application layer. However, implementing something at the OS layer with the expectation of exposing it directly to the user goes against the current thinking that it's the application layer's job to provide user-friendly concepts, and that the job of the OS is merely to support the application layer in doing that. If providing support for application-level user-friendly abstractions is what you want to do, then I would suggest studying applications with UI abstractions that you admire and judging your OS storage layer by how well it supports application development.