Software Engineering-Software Process Models

To solve actual problems in an industry setting, a software engineer or a team of engineers must incorporate a development strategy that encompasses the process, methods, and tools layers and the generic phases. This strategy is often referred to as a process model or a software engineering paradigm. A process model for software engineering is chosen based on the nature of the project and application, the methods and tools to be used, and the controls and deliverables that are required.

All software development can be characterized as a problem solving loop in which four distinct stages are encountered: status quo, problem definition, technical development, and solution integration. Status quo “represents the current state of affairs”; problem definition identifies the specific problem to be solved; technical development solves the problem through the application of some technology, and solution integration delivers the results (e.g., documents, programs, data, new business function, new product) to those who requested the solution in the first place. The generic software engineering phases and steps easily map into these stages.

This problem solving loop applies to software engineering work at many different levels of resolution. It can be used at the macro level when the entire application is considered, at a mid-level when program components are being engineered, and even at the line of code level. Therefore, a fractal representation can be used to provide an idealized view of process. Each stage in the problem solving loop contains an identical problem solving loop, which contains still another problem solving loop.

Realistically, it is difficult to compartmentalize activities implies because cross talk occurs within and across stages. Yet, this simplified view leads to a very important idea: regardless of the process model that is chosen for a software project, all of the stages—status quo, problem definition, technical development, and solution integration—coexist simultaneously at some level of detail. Given the recursive nature of Figure 2.3b, the four stages discussed apply equally to the analysis of a complete application and to the generation of a small segment of code.

Raccoon  suggests a “Chaos model” that describes “software development as a continuum from the user to the developer to the technology.” As work progresses toward a complete system, the stages are applied recursively to user needs and the developer’s technical specification of the software.