So, Julius — my friend: you are wrong. So, so wrong.
The reason that storage media appears to be much smaller than advertised is not because of buffer or some hardware reason. It’s because the units advertised on the box and the units displayed by the software are not the same units! The difference is, the media manufacturers use decimal representation (kilobyte = 1,000 bytes) and the software uses binary representation (kilobyte = 1,024 bytes).
(As you probably guessed, a 2.3% margin of error multiplied by 10242 is pretty off.)
A perfect example of how one question can set me off on about 2-3 hours of research. 
