GUID guide, part two

So how is it that a GUID can be guaranteed to be unique without some sort of central authority that ensures uniqueness, a la the ISBN system? Well, first off, notice that the number of possible GUIDs is vastly larger than the number of possible ISBNs. Because the last of the thirteen digits is a checksum, there are only 1012 possible ISBNs. That is about a hundred unique ISBNs for every person on earth. That's almost exactly 240, so you could rep...

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