Re: In the absence of files...
> Whether you call something a directory or a folder it's still an abstraction of a place in which to store other things, some of which may also be files or folders depending on the vocabulary you choose to use. You're confusing the abstraction with its implementation.
No - a directory is *not* "a place to store something" - it is an indirection, a reference to where the thing is stored.
Joe Bloggs is not "stored" in any of the paper directories - finding a reference to Joe then points to his physical location (or to another reference that you can then follow to finally reach him physically - e.g. a 'phone number).
>> Folders are a physical box to put things in. I put the thing in box A, it's still in that box later. I move it to box B, it's not in box A anymore.
That is why adding or removing a reference to Joe does not change the way he is stored, nor does it change any of the other references.
Similarly[1] a file system's directory entry is *not* the file itself, it is a reference to where the file can be found. You will often "move" a file from one directory to another, but that is conflating two directory operations into a single command: add the new dir entry, then delete the old dir entry. At no point[1] does the file itself change its location during this move.
The semantics of a "folder" and a "directory" are very different, but everyone continuing to use the UI term "folder" is clearly confusing/limiting people's thinking.
[1] ignoring later optimisations that were added to the file systems, like storing the contents of a tiny file inside its directory node - which then causes all sorts of fun when you create another link to reference that data