"Agile methods" software development (also called Agile Modelling denoted AG for short) reduce software lifecycle time (thus speeding up development) by firstly developing a prototype version, then integrating functionality on an iterative basis responding to customer requirements and testing throughout the development cycle
Agile methods originate from the instability of the technical environment and the fact that the client is often unable to define every single requirement at the start of the project. The term "agile" is a reference to the ability to adapt to contextual changes and changes to specifications which occur during the development process. Thus in 2001, 17 people came up with the agile manifesto the main points of which are as follows:
Rapid Application Development (or RAD) was defined by James Martin in the early 1980s, and consists of a short development cycle based on 3 phases (Requirements, Design and Construction) with an ideal delivery time of between 90 and 120 days maximum.
The DSDM (Dynamic Software Development Method) was developed to fill in some of the gaps in the RAD method by providing a framework which takes into account the entire development cycle.
The main features of the DSDM method are as follows:
The Unified Process UP method is an iterative and incremental development process which means that the project is cut into very short phases, where a new incremental version is delivered at the end of each phase.
RUP (Rational Unified Process) is an iterative development method promoted by the Rational Software company, which was bought by IBM.
The XP method (EXtreme Programming) defines a set of best practices for application development in optimal conditions by placing the customer at the centre of the development process, maintaining a close relationship with the customer.
Extreme Programming is based on the following concepts: