Waterfall vs. RUP Software Engineering in Plain English

This post compares and contracts Waterfall and RUP software engineering approaches with a construction analogy. Why specifically these two approaches? Waterfall is representative of conventional methodology, while RUP is contemporary, moving towards Agile Development.

The project at hand is the construction of three apartment complexes, A1 A2 and A3. The project is planned to be completed in three months, Jan Feb and Mar. For simplicity, assume that the project involves three primary processes, structuring, plumbing and landscaping.

Lets see how this project will be handled in the Waterfall approach and RUP approach.

The Waterfall Square Apartments

Waterfall, one of the earliest software engineering principles, is a top-down approach. It proposes that the key processes in a project must be performed sequentially, one at a time.

Firstly, we know the three key processes are: structuring, plumbing and landscaping. Waterfall directs us to perform the tasks in sequence – each task in one 'big bang'. Do it once, do it right!

So Month 1, Jan, we take on the structuring work for all the three complexes, A1, A2 and A3. In Feb, we concentrate on getting all the engineering done for all three complexes. In Mar, we finish the project by landscaping for A1, A2 and A3.

This is how the plan will look like this:

And this is how the construction will progress over the three months visually:

The RUP Hill Apartments

RUP, one of the newer software engineering principles, is a top-down approach. It recommends that first, key sub-projects in the project be identified (and in what order they must be developed). Then, take on each sub-project and repeat the key processes.

We can break the bigger problem into three sub-problems: A1, A2 and A3. Based on the RUP principle, we first take A1, perform the tasks (structuring, engineering and landscaping) then repeat for A2 and then repeat for A3.

Jan will take on A1, completing structuring, engineering and landscaping. Then, A2's structuring, engineering and landscaping gets done in Feb. Repeat for A3 in Mar.

This is how the plan will look like this:

And this is how the construction will progress over the three months visually:

RUP is called an iterative and incremental model. Iterative, since we repeat the processes in each iteration(A1, A2 and A3 were out iterations). Incremental since each iteration contributed to expanding the project towards it completion.

How is RUP is better than Waterfall?

RUP and Agile Methods are predominantly used in contemporary projects. What are the advantages of RUP over Waterfall? Try to use this construction example without getting too technical. Please use the comments below!

What process are you using in your current project? Share with us!

Here is a video snippet from a trial class of our Full Cycle Business Analysis where we discuss this Waterfall vs. RUP scenario. Register for a trial class.