Now that you have learned about the outer circle of the ISD model (the changing environment) and its five system functions,
it's time to move on to the inner part of the circle, which depicts the phases
of ISD.
If we take the outer circle that represents the changing environment
and the system functions, and then add in the inner part of the circle, the phases, our model now looks like this.
You'll notice there are five system phases in our ISD model: analysis, design, development, implementation, and once
again, evaluation.
