System Dynamics is the process of modeling systems in feedback loops. Developed by computer scientists at MIT, System Dynamics as a technical approach eventually fell out of fashion in favor of formal verification. And yet as we build distributed applications and the environment of automation to support them we see more and more outages triggered by dysfunctional feedback loops. These problems are impossible to model in formal verification but can be reasoned about in System Dynamics. This talk will discuss the history of System Dynamics, what tooling is available for software engineers to build and run models, and how to represent various architectures using the abstractions of System Dynamics.—Marianne Bellotti @ SREcon21 usenix 
youtube pdf
YOUTUBE wcMN1xaJnzs
Let's Bring System Dynamics Back to CS! — Marianne Bellotti @ SREcon21 usenix youtube
Bellotti is developing Fault language: github
Suggests some opensource and free tools for building systems dynamics models.
Nickie Case's Loopy app
Insight Maker site
Simlin site
PySD docs
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Bellotti wrote the book Kill It With Fire about her experience rescuing or retiring critical legacy systems. We summarized another talk which takes inspiration here: To Kill It or Not Kill It With Fire?
Bellotti points to origins of System Dynamics in computer scientists who participated in Cybernetics.
Ward reports disappointment in the naive descriptions of thermostats conventionally given to introduce System Dynamics concepts. He offers a graphviz model.
We have conversations about modeling system dynamics in wiki: System Dynamics.
Recent work to port Plumbin' to wiki reaches in the direction of similar modeling of System Dynamics. We have flows. Is a tank an example of a stock? It is at least very close. See Plumbin' in Wiki.
Causal Loop Diagrams and their companion narratives offer a less formal method (pun intended) of inquiry. wikipedia See Causal Loops.