Systems Architecture

The major share of modern system functionality is implemented in software: Embedded in devices and sensors in the field, centralized in cloud backends, or running on edge devices like smartphones or laptops.

The system interacts with the physical environment through spatially distributed sensors and actors. Functionality is determined largely by digital algorithms.

The systems consists of many interconnected computing nodes that run software asynchronously and independently. Nodes may reside in physically separated locations, and may be mobile. Individual nodes and communication links may go down at any point in time.

The system is characterized by its many constituent parts, a high degree of interconnectedness, a very large state space, or computationally intensive decision-making on the basis of many input variables. Thus, the system most often cannot be described in simple, deterministic terms; humans are not able to understand and reason about all causal chains and all error conditions.

The system interacts with its environment via a number of interfaces – user interfaces as well as interfaces to other systems.

The system comprises of technical as well as social components; e.g., employees, drivers, customers, or patients. The technical and social components interact and make system behaviour unpredictable.

The system forms part of an existing infrastructure, or will be infrastructure by itself.

The system may directly or indirectly influence the health or well-being of persons, threaten property, invade privacy, or impede operation of processes or institutions of our civil society.

The system is designed for an operational lifespan of more than ten years. Fundamental architectural decisions outlast the concrete implementation. Changing the architecture will be virtually impossible or take a disproportionate effort.