Meaning, there are 1 million bytes of storage, but pretty much all filesystems use some of those bytes to represent information
about the files in addition to the files themselves. Hence, formatted, the resulting filesystem will have capacity less than that.
You could, if you really wanted to, write 1 million raw bytes to the disk. But you'd need special software to read and write it, because de facto software expect there to be a master partitioning table or whatever it's called.
