Page 1405 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide
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FIGURE 20.3 The spiral lifecycle mode
Notice that each “loop” of the spiral results in the development of a
new system prototype (represented by P1, P2, and P3 in Figure 20.3).
Theoretically, system developers would apply the entire waterfall
process to the development of each prototype, thereby incrementally
working toward a mature system that incorporates all the functional
requirements in a fully validated fashion. Boehm’s spiral model
provides a solution to the major criticism of the waterfall model—it
allows developers to return to the planning stages as changing
technical demands and customer requirements necessitate the
evolution of a system.
Agile Software Development
More recently, the Agile model of software development has gained
popularity within the software engineering community. Beginning in
