person Author: Process Fellows
There are various approaches available how to define a system architecture. One exemplary approach uses views like a functional architectural view, a logical architectural view and a physical architectural view.

1. Functional Architecture: The functional architecture defines what the system must do. It describes the system’s functions, their inputs and outputs, and how they interact to fulfill the system’s purpose. This level is technology-independent and focuses purely on the capabilities and behavior of the system.
   Example: A car’s functional architecture might include functions like “accelerate,” “brake,” “steer,” and “monitor speed.”
2. Logical Architecture: The logical architecture defines how the system functions are logically grouped and interact. It introduces logical components and their interfaces, but still remains independent of the concrete physical parts. It serves as a bridge between functional needs and physical realization.
   Example: In the car example, logical components might include “Powertrain Control Unit,” “Brake Control Module,” and “User Interface Module,” each responsible for a set of functions. So, it could be decided already that there is the need e.g. for a CPU, but this is more like a categorization and it is not about picking a concrete physical part!
3. Physical Architecture: The physical architecture defines with what the system is implemented. It maps the logical components to real hardware, software or mechanical parts, including e.g. sensors, actuators, processors, and communication buses. This level is technology-specific and considers constraints like cost, space, and performance.
   Example: The “Brake Control Module” might be implemented using a specific microcontroller, connected to wheel speed sensors and hydraulic actuators.