As software-intensive systems continue to grow in scale and complexity the techniques that we have used to design and analyze them in the past no longer suffice. In this paper we look at examples of existing ultra-large-scale systems—systems of enormous size and complexity. We examine instances of such systems that have arisen spontaneously in nature and those that have been human-constructed. We distill from these example systems the design primitives that underlie them. We capture these design primitives as a set of tactics— fundamental architectural building-blocks—and argue that to efficiently build and analyze such systems in the future we should strongly consider employing such building-blocks
