A little over a year ago I met with another tester in town to provide advice on performance testing. I recently found the notes from the meeting in an old notebook. In the five pages of handwritten notes, I documented my understanding of the problem and how I would approach the project. Take these notes for what they are - sketches over the course of an hour or two as I asked questions and clarified the project. However, I thought they would be interesting to share.
The first page was an interactive attempt to understand the problem.
To protect the company (who might not want to be identified) I won't provide more details than what's in the picture, but what I remember was that it emerged over a series of questions where I asked things like: "And that's connected to?", "And that gets its data from where?", and "That's not on here yet, where does it go?"