Can't speak to the sequel as I gave up on the series after that, but it's _really_ not relevant to the plot or ideas of the first book at all. All that matters for the plot is that a hostile, powerful, uncontrollable AI arises. In the book, it _happens_ to be because of a code archeologist "delving too greedily and too deep"; but the plot would not be changed one iota if it had simply arisen (and gone off the rails) as a product of general AI development.