Then the fact that recording something on the disk doesn't affect the mass doesn't matter, does it ?
Is this even true?
Since reading Meyers' question I am not convinced that even the basic premise is true.
I could just as well do the same thing with two jotters, in one of which I had written my name, but I would be falsely claiming that the mass had not changed. The ink or graphite I used to write would have changed the mass, but not in a range easily detectable without sophisticated equipment.
I think Meyers' claim is similarly dubious, I am not convinced that the changes in ferromagnetic states or the changes in optical dyes which are used in most of our modern recording media do not come with associated changes in mass/energy. These changes may not be readily measurable but that does not mean that they don't exist.
TTFN,
WK
P.S. I could be wrong here, my physics never went beyond high school.