Chapter 4: Process Models
4.5. As you move outward along the spiral process flow, what can you say about the software that is being developed or maintained?
As work moves outward on the spiral, the product moves toward a more complete state and the level of abstraction at which work is performed is reduced (i.e., implementation specific work accelerates as we move further from the origin).
4.4. Provide three examples of software projects that would be amenable to the incremental model. Be specific.
Each linear sequence produces deliverable "increments" of the software for example, word-‐processing software developed using the incremental paradigm might deliver basic file management, editing and document production functions in the first increment; more sophisticated editing and document production capabilities in the second increment; spelling and grammar checking in the third increment, and advanced page layout capability in the fourth increment. The process flow for any increment may incorporate the prototyping paradigm. Incremental development is particularly useful when staffing is unavailable for a complete implementation by the business deadline that has been established for the project.
4.6. Is it possible to combine process models? If so, provide an example. The process models can be combined, each model suggests a somewhat different process flow, but all perform the same set of generic framework activities: communication, planning, modeling, construction, and delivery/feedback.
For example the linear sequential model can serve as a useful process model in situations where requirements are fixed and work is to proceed to completion in a linear manner. In cases, where the developer may be unsure of the efficiency of an algorithm, the adaptability of an operating system, or the form that human-‐machine interaction should take. In these, and many other situations, a prototyping model may offer the best approach. In other cases, an incremental approach may make sense and the flow of Spiral model may be efficient. Special process models take on many of the characteristics of one or more of the tradition.
4.3. What process adaptations are required if the prototype will evolve into a delivery system or product?
If a prototype is evolved into a delivery system or product, it begins with communication. The software engineer and customer meet and define the overall objectives for the software, identify whatever requirements are known, and outline areas where further definition is mandatory. The prototype serves as a mechanism for identifying software requirements. If a working prototype is built, the developer attempts to make use of existing program fragments or applies tools (e.g., report generators, window managers, etc.) that enable working programs to be generated quickly.
4.2. Provide three examples of software projects that would be amenable to the prototyping model.
Software applications that are relatively easy to prototype almost always involve human-‐machine interaction and/or heavy computer graphics. Other applications that are sometimes amenable to prototyping are certain classes of mathematical algorithms, subset of command driven systems and other applications where results can be easily examined without real-‐time interaction. Applications that are difficult to prototype include control and process control functions, many classes of real-‐time applications and embedded software.
4.1. Provide three examples of software projects that would be amenable to the waterfall model. Be specific.
The waterfall model is amenable to the projects that focus on the attributes such as the data structures, software architecture, and procedural detail and interface characterization of objects.