Category Archives: system thinking

FAQ: Digital Machine Theory 0.5beta

What is Digital Machine Theory?

It is a method I am developing to teach systems design to interaction design students.

I believe the theory demonstrates how to connect classical systems theory of the Forrester/Meadows school to the practice of interaction design.

The primary assertion is that interaction design may be understood as the design of a digital machine defined in terms of cybernetic principles.


I am not familiar with the terminology used to describe Digital Machine Theory.  Do you have a plain language presentation?

Why yes, I do!

I have prepared a series of 6 short lectures that explain the theory in plain language:

  1. What is a system?
  2. From System to Software
  3. The Conceptual Model
  4. The Interaction Model
  5. The Object Model
  6. The Data Model

What is the value of digital machine theory?

I propose the theory has value as:

  1. a theoretical framework to train individuals in the basics of software design practice
  2. a communication framework for planning the design or redesign of a software application

How did you come to develop it?

It is an outcome of my work as adjunct professor at California College of the Arts Interaction Design Program.  I teach a course called Systems to undergraduates.

Why are you calling it a beta release?

Because I am a nerd.  Also because I feel like beta sets an appropriate (in my world, at least) expectation for the quality level of both the theory itself and the materials I have put together to explain it.  I think it has some good bones, but the whole thing needs some banging on still.  Do so and send me comments, timsheiner at

On the relationship between system, interaction and business models

A very short post to share a simple formulation I have developed for explaining the relationship between the models I find most central in developing interactive systems.

First, a high level statement presenting the models and their relationship:

<business model><interaction model><system model>.

My meaning with respect to the “><” is that you can read this statement from left to right or right to left, or start in the middle.  This is because all the models are connected through feedback loops.

Your choice about where to begin depends on what you know initially, what most interests you, or what direction you want to drive change.

A presentation of the overall system of models in a tree, with more detail about their respective composition is this:

  • Business Model
    • Value Proposition
    • Cost Model
    • Revenue Model
  • Interaction Model
    • Conceptual Model
    • Object Model
    • Data Model
    • Error Model
  • System Model
    • Purpose
    • Objects
    • Relationships

And there it is.