Is concurrency hard?
Richard A. O'Keefe
Thu Nov 3 03:02:42 CET 2005
Joe Armstrong (AL/EAB)" <> wrote:
Now in physics there is no concept of sharing and no concept of
simultaneity at a distance. We can only say that two things
occur at the same time if they occur at the same place.
Actually, in physics, there _is_ a notion of a 'timelike slice'.
But it has long seemed to me that mutable variables are basically a
device for providing instantaneous communication between remote parts of
a program, so there has to be something wrong with them.
The plain fact of the matter is that *programming* is hard.
Some languages make some things harder to program than others.
I remember reading a book about JSP years ago, which said that it
was basically a way of letting you simulate a collection of millions
of concurrent objects by inverting their code, and I wondered at the
time "why not just use a programming language that lets you have
millions of concurrent objects"? (The target language was in fact COBOL.)
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