Which methodologies use waterfall strategy and which use incremental strategy?

Question

I know difference between waterfall and incremental strategies. But I'm somewhat confused because I see that there are methodologies which use incremental or iterative approach but I cannot see any examples for waterfall strategy.

For example Scrum is a methodology that uses incremental or iterative strategy but is there any examples for methodologies that use waterfall strategy? Or is waterfall itself a methodology?

Answer 1

You're absolutely right. Waterfall is itself a methodology. It also has a bunch of variants, the most known being V-Model.

As Scrum, XP and others would be qualified as iterative strategies, Waterfall and V-Model are qualified as linear strategies.

Answer 2

The Waterfall Model is a methodology. It's not called the "Waterfall Methodology" only because when it was invented, they used the term "Model" instead.

The Waterfall Model was described by Winston Royce in his 1970 article Managing the development of large software systems, although he did not use the term "Waterfall" (that was coined later, in reference to how the artifacts flow from step to downward).

In the beginning of the article, he described what we now know as "Waterfall". He particularly described Waterfall as an example that doesn't work, because it is too simplistic.

In the middle of his article, Royce then analyzes Waterfall, and explains everything that is wrong with it, and in the last third of the article, he explains how to fix it, and describes a fixed version. This fixed version is incremental and iterative, and even incorporates some ideas that we would today recognize as "Agile", such as prototyping, continuous customer involvement and feedback, and short feedback cycles.

Unfortunately, Royce's "example of a process that is too simplistic to possibly work" was actually so simplistic that people just looked at the pretty diagram on the top of page 2:

Source: Figure 2 on p. 329 of Managing the development of large software systems, Dr. Winston W. Royce (1970) in: Technical Papers of Western Electronic Show and Convention (WesCon) August 25–28, 1970, Los Angeles, USA.

And they implemented it, without even bothering to read the rest of the paper and realizing that this process was explicitly designed as an example of a non-working process. I think it was Glenn Vandenburg, who called the article an "example of horrible information design": the article is titled "Managing the development of large software systems" and it starts off with a nice diagram of a process for, well, managing the development of large software systems, and the fact that this process doesn't work is actually hidden in the text.

What he was actually proposing, was this:

Source: Figure 10 on p. 338 of Managing the development of large software systems, Dr. Winston W. Royce (1970) in: Technical Papers of Western Electronic Show and Convention (WesCon) August 25–28, 1970, Los Angeles, USA.

Answer 3

The Waterfall model is the earliest SDLC approach that was used for software development. The waterfall Model illustrates the software development process in a linear sequential flow. This means that any phase in the development process begins only if the previous phase is complete.