>It's not my fault that a file system uses up more space storing the same amount of data in two files rather than a single file.
Even without a filesystem - just sending data over the wire - you have to be able to delimit files in some way, and there's going to be overhead associated with that.
Another way to think of this is that any particular volume could be viewed as a single big file. How much space in that big file is he taking up?