  The paper explains why Amdahl's Law shall be interpreted specifically for
distributed parallel systems and why it generated so many debates, discussions,
and abuses. We set up a general model and list many of the terms affecting
parallel processing. We scrutinize the validity of neglecting certain terms in
different approximations, with special emphasis on the famous scaling laws of
parallel processing. We clarify that when using the right interpretation of
terms, Amdahl's Law is the governing law of all kinds of parallel processing.
Amdahl's Law describes among others the history of supercomputing, the inherent
performance limitation of the different kinds of parallel processing and it is
the basic Law of the 'modern computing' paradigm, that the computing systems
working under extreme computing conditions are desperately needed.
