Scale Changes Everything: Understanding the Requirements for Systems of Systems

Summary form only given. Software technology now penetrates almost every aspect of our lives in complex ways. The reality of 21st century software development is that software itself is but one part of a complex system-of-systems that includes a broad technological infrastructure along with a wide set of human activities. The technological systems and the human activity systems have a symbiotic relationship - each shapes the other in complex ways, such that neither can be understood in isolation. A recent report from the SEI on ultra-large scale (ULS) systems accurately characterized the nature of these systems-of-systems: they have no centralized control; experience normal failures and continual evolution of heterogeneous elements; and their requirements are inherently conflicting, diverse and often unknowable. For design purposes, the boundary between people and software disappears - design is as much about shaping the human activities as it is about constructing the software