Chapter 15: Software Life Cycle
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Abstract
A software life cycle model represents all the activities and work products necessary to develop a software system. Life cycle models enable managers and developers to deal with the complexity of the process of developing software in the same way as an analysis model or a system design model enables developers to deal with the complexity of a software system. In the case of software systems, the reality being modeled includes phenomena such as watches, accidents, trains, sensors, and buildings. In the case of software development, the reality includes phenomena such as participants, teams, activities, and work products. Many life cycle models have been published in the literature in an attempt to better understand, measure, and control the development process. Life cycle models make the software development activities and their dependencies visible and manageable.
In this chapter, we revisit the activities described in previous chapters from the perspective of life cycle modeling. The modeling techniques we used for modeling software systems can also be used to represent life cycles. Whereas life cycle models are usually represented with ad hoc notations, we try to use UML diagrams whenever possible. First, we describe the typical activities and work products of a software life cycle as defined by the IEEE standard 1074 [IEEE Std. 1074-1997]. Next, we introduce the Capability Maturity Model, a framework for assessing the maturity of organizations and their life cycles. We then discuss different life cycle models that have been proposed for developing complex software systems; these include the waterfall model, the spiral model, the V-model, and the unified software process. We also discuss a life cycle model called the issue-based model, in which products and activities are modeled as a set of issues stored in a knowledge base. The issue-based model is an entity-centered view of the software life cycle that can accommodate frequent changes over the duration of a project.