Product Lifecycle Management - Ahmedabad Software..!

Life cycles are usually referred to as models, and define the phases of a software development effort. Simple life cycles may have only three phases, Design, Development, and Maintenance; while complex life cycles may include 20 or more phases. Generally, software life cycles include the phases shown in
Figure 2-1.

There are many life cycle models, or paradigms. Most of them are variations of three classic software development models: the waterfall, incremental, and spiral models. These three, along with the evolutionary model, are summarized here.

Advanced Lifecycle Model
This model, also known as the linear sequential model, is shown in Figure 2-2 with its major phases, milestones, and products. It is a highly structured development process, first used on DoD software projects in the 1970s.

It is the “traditional” approach to software development and was derived from defense and aerospace project lifecycles.
It is considered superior to the previously used “code and fix” methods of software development, which lacked formal analysis and design.

Spiral Model

The evolutionary model, like the incremental model, develops a product in multiple cycles. Unlike the incremental model, which simply adds more functionality with each cycle, this model produces a more refined prototype system with each iteration. The process, shown in Figure 2-3, begins in the center with initial equirements and plans, and progresses through multiple cycles of planning, risk analysis, engineering, and customer evaluation. Each cycle produces a prototype that the customer evaluates, followed by a refinement of requirements.