Why Do Software Engineers use models?

Answer 1

The idea of visually modeling software, and the tools to support this endeavor, have been

around for a few years. However, many developers and project managers may not understand

why this is important to software development. Sometimes the project managers understand

the rationale for modeling tools, but they must convince upper management, who ultimately

must give authority for a relatively large software purchase.

This white paper gives an overview of the justification for modeling, as well as a rationale for

the use of a modeling tool. It also describes the minimum feature set that any modeling tool

should have.

Why model?

"If you were supposed to understand it, we wouldn't call it code." -- from a Federal Express

promotion, reported by IS Survivalist Matthew Persico

Some development managers wonder why modeling is important at all. After all, the code

should speak for itself. In essence, the code is the model. Why add an extra layer of

abstraction that we have to maintain as the project progresses? The reason is that there are a

number of clear benefits that models provide a development organization. They are enhanced

communication, better planning, reduced risk, and reduced costs.

Enhance communication

The beginning of the legal description for my plot of land is shown in Figure 1. If you were a

surveyor, you would be able to take the full description and draw my lot, and point to a map

and show me exactly where my house is. To a surveyor or lawyer, this is the "code" that

describes the land that I own. While this is an exact description of my property, this is not a

natural way of viewing the world. Given the description above, an experienced surveyor

might have a general idea of what my lot looks like, what direction it faces, and so on. He

Software Modeling Introduction - Why do I need a modeling tool?

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could put a picture in his mind for this plot of land. However, even this is not a natural thing

for any person, no matter how mathematically inclined they might be. Anyone will want to

see a drawing of the land. As you can see, the lot is relatively plain - roughly rectangular in

shape, nothing extraordinary.