Extreme Programming (XP) Ref.[10] is a software engineering methodology based on an informal process and it is defined by a series of rules and guidelines. It is probably the most popular of several agile software development methodologies. It is especially targeted to small to medium projects with a focused scope.

XP prescribes a set of 12 day-to-day practices for managers and developers, like Pair Programming, Test-Driven Development (see 3.6.9), Continuous Integration, etc. XP sets out to reduce the cost of change by introducing basic values, principles and practices.

The five values of XP are: Communication; Simplicity; Feedback; Courage; Respect.

The principles that form the basis of XP are: Feedback; Assuming Simplicity; Embracing Change.

Compared to RUP it places a higher value on adaptability. In XP it is foreseen that changes to requirements can happen during a software development project. Therefore, XP is able to adapt to changing requirements at any point during the project life time. By applying XP, a system development project should be more flexible with respect to changes.

XP describes four basic activities that are performed within the software development process:

Coding; Testing; Listening; Designing

Goals of XP:

• An attempt to reconcile humanity and productivity;
• A mechanism for social change;
• A path to improvement;
• A style of development;
• A software development discipline.

Links:

http://www.xprogramming.com/
http://www.extremeprogramming.org/
http://en.wikipedia.org/wiki/Extreme_Programming