By:  Sylvain Chery (Director) and Guy Fabien (Senior Consultant) @ Agile Partner

Preamble

To better understand the emergence of Agility and methods based thereon, it appears necessary to present a brief history of the major phases that have marked the evolution of programming in the field of computing.

Let me start by introducing the concept of "life cycle of software."

The "life cycle of a software" is a concept that has been defined to describe the steps of software development, from its conception to its demise. The goal is to, first, to track the development of software by ensuring compliance with the expressed needs and checking the adequacy of methods used with order considered, and secondly to allow monitoring and evaluation of how the software is operated from its availability to users until replaced or withdrawn.

The duty of memory

The evolution of software development has been marked by the creation of multiple methods of implementing various concepts and varied. We present below the main illustrating the progression and evolution of important concepts.

1) Waterfall Style: Original

The waterfall model is inherited from the construction industry. This model is based on assumptions that can not build the roof before the foundation and the consequences of a change in front-end have a major impact on downstream costs.

2) V-model: the improvement is running

The V-cycle model has been devised to overcome the problem of reactivity of the Waterfall model. This model is an improved Waterfall model that allows in case of anomalies, limited return to previous steps. The phases of rising part should return information about the phases in opposite when defects are found to improve the software.

The V cycle has become an industry standard software development and project management since the 1980s.

3) Spiral model: the second revolution

Development is based on the different stages of the V cycle to allow a product to produce more and more complete through the creation of earlier drafts.

4) Model semi-iterative: the idea is emerging

Semi-iterative cycle originates in the work of James Martin in 1989 published in various North American journals. It was completely formal in the 1991 book RAD (Rapid development of applications). Since 1994, additional research carried out in France (RAD2) and England (DSDM) brought specializations initial basic techniques. The success of RUP (Rational Unified Process) devoted the peak of this cycle is still in force in large projects.

5) Iterative model: the principle is laid

It separates the activities of artifacts, knowing that artifact is the product of an activity. Thus, we apply a cycle type of Deming's wheel on the production of documentation, code, a test. It is therefore to deliver earlier than something that can be tested by the customer.

As a first observation

Thus through this small retrospective, it is interesting to note that Agility, which is based on an iterative model (last model to be created) is not only the result of the analysis and evaluation of several years of experience and practice in managing IT projects but also the result of a need to minimize the possible impact of costs related to the occurrence of errors throughout the life cycle of development Software.