2.2 Project life cycle. Phases and Products

It has already been noted that each software product has its own life cycle, in which the project of developing the next release enters as one of the phases. Similarly, each software development project has its own life cycle, which consists of four phases (Figure 12).

Figure 12. Life cycle and main products of the software project

At the project initiation phase, it is necessary to understand what we are going to do and why - to develop a project concept. The planning phase determines how we will do it. In the implementation phase, the materialization of our ideas takes place in the form of a documented and tested software product. And finally, during the completion phase, we must confirm that we have developed exactly the product that we conceived in the project concept, and also carry out an acceptance test (PSI) of the product for compliance with its properties, as previously defined.

As a rule, a rare project is carried out in accordance with the original plans; therefore, an important element of the completion phase is “feedback”: an analysis of the causes of discrepancies and the assimilation of lessons for the future. Remember that a control system without feedback cannot be stable.

In more detail about each phase of the project and their products will be discussed in subsequent lectures.

Completing the “bird's-eye view” project management review, it is necessary to mention one more peculiarity of the project as compared with the operational activity. If in operating activities resources are spent more or less evenly in time, in project management the expenditure of resources per unit of time has a pronounced bell-shaped distribution (Figure 13)

Figure 13. Resource allocation by project phases

A project often begins with an idea that appears in one person. Gradually, as the idea is formulated, analyzed and assessed, additional specialists are involved. More participants are required in the project planning phase. Peak resource consumption occurs during the implementation phase.

In modern software development models, implementation is based on a combination of iterative and incremental approaches.

Iteration implies that the requirements for the system and its architecture are not worked out once, but are gradually refined from iteration to iteration. This means that at each iteration there is a full cycle of development processes: specification of requirements, design, coding, testing and documentation.

The incrementality is that the result of each iteration is a software version that implements some of the functionality of the future software product and can be put into test or trial operation, as well as evaluated by the customer and future users. This means that after each iteration an increase in the required functionality occurs, and the unrealized functions of the future product remain less and less.

The combination of iteration and incrementality ensures the development efficiency and a significant reduction of risks during the project. We will talk about this later.

In the last phase, gradual release of the project team members takes place. It should be remembered that the project should have a clear ending in time, after which all the work on the project is closed, and resources cease to be spent on the project. There should be no "stuck" work.

findings

The project is a means of strategic development. The goal is a description of what we want to achieve. Strategy - a statement of how we are going to achieve these goals. Projects transform strategies into actions, and goals into reality.

Participants in a typical software development project can be divided into five groups of roles:

1. Analysis. Extract, document and maintain product requirements.
2. Control. Definition and management of production processes.
3. Production. Software design and development.
4. Testing. Software Testing.
5. Security. Production of additional products and services.

A software project has four factors that determine its success:

1. Made in accordance with the specifications.
2. Done on time.
3. Completed within budget.
4. Each team member left work at 6:00 pm with a sense of success.