Systems

Biological systems is what works (simple, layered. hierarchical). Think of whole societies or big cities (shared environments) of individual programs or pure-functional /services. Erlang is the best (well-researched) model.

• A higher level than (an aggregate of) individual programs.
• In a communication network (shared environment).
• Failures are present all the time (expect everything to fail).
• Always in the state of a partial failure (something is not as expected).
• No centralized control (ideally).