2.1 Process and Project

A process is a sequence of steps performed for a given purpose [52]. As mentioned earlier, while developing (industrial strength) software, the purpose is to develop software to satisfy the needs of some users or clients, as shown in Figure 2.1. A software project is one instance of this problem, and the development process is what is used to achieve this purpose.

 

Figure 2.1: Basic problem.

So, for a project its development process plays a key role—it is by following the process the desired end goal of delivering the software is achieved. However, as discussed earlier, it is not sufficient to just reach the final goal of having the desired software, but we want that the project be done at low cost and in low cycle time, and deliver high-quality software. The role of process increases due to these additional goals, and though many processes can achieve the basic goal of developing software in Figure 2.1, to achieve high Q&P we need some “optimum” process. It is this goal that makes designing a process a challenge.

We must distinguish process specification or description from the process itself. A process is a dynamic entity which captures the actions performed. Process specification, on the other hand, is a description of process which presumably can be followed in some project to achieve the goal for which the process is designed.

In a project, a process specification may be used as the process the project plans to follow. The actual process is what is actually done in the project. Note that the actual process can be different from the planned process, and ensuring that the specified process is being followed is a nontrivial problem. However, in this book, we will assume that the planned and actual processes are the same and will not distinguish between the two and will use the term process to refer to both.

A process model specifies a general process, which is “optimum” for a class of projects. That is, in the situations for which the model is applicable, using the process model as the project’s process will lead to the goal of developing software with high Q&P. A process model is essentially a compilation of best practices into a “recipe” for success in the project. In other words, a process is a means to reach the goals of high quality, low cost, and low cycle time, and a process model provides a process structure that is well suited for a class of projects.

A process is often specified at a high level as a sequence of stages. The sequence of steps for a stage is the process for that stage, and is often referred to as a subprocess of the process.