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Deepak Mehta, Lovely Professional University Unit 3: Process Models

Unit 3: Process Models Notes

CONTENTS
Objectives
Introduction
3.1 Prescriptive Models
3.1.1 Waterfall Model

3.2 Incremental Process Models
3.2.1 Incremental Model
3.2.2 RAD Model
3.3 Summary
3.4 Keywords
3.5 Review Questions
3.6 Further Readings

Objectives

After studying this unit, you will be able to:
Recognize the perspective model
Describe the incremental models

Demonstrate the waterfall model
Explain the RAD model

Introduction

There are three major models of the software engineering process. The waterfall model was for
many years the front runner and is required for many military applications. (The procurement
process of the US military has had a profound effect on computer science and software engineering
in particular.) It is a rigid system well suited to applications where the buyer is as sophisticated
about computer systems as the seller.
Prototyping is popular with those who work in the marketplace of “user friendly” software.
This software is historically less maintainable (and less maintained) than the so called “big
iron” applications that were historically developed using the waterfall model. The incremental
model works from the notion that software is built. The Spiral model is a more recent model
that tries to enjoy the best of both worlds. Each of these models shares some common features.
In particular they all involve establishing the requirements that the system is to meet.

3.1 Prescriptive Models

Prescriptive process models advocate an orderly approach to software engineering that leads to
a few questions

If prescriptive process models strive for structure and order are they inappropriate for a
software world that thrives on change?

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