RUP in the dialogue with Scrum
There is a relation between Agile and RUP. Actually I though that Agile development was a type of RUP. In the article from IBM above you can see that they are fitting the model to RUP.
Does someone has any practical explanation of the relation between these three interesting concepts.
They are both iterative models which seem similar, but both of them are vastly different. Scrum is an Agile iterative increment model, while RUP is a framework. RUP is a framework for organizations and teams while Scrum is intended for a product team with stringent guidelines.
I'd suggest you read these: http://en.wikipedia.org/wiki/Scrum_(development) http://en.wikipedia.org/wiki/IBM_Rational_Unified_Process
Agile is an approach to software development:
(quoted from the Agile Alliance website)
What Is Agile Software Development?
In the late 1990’s several methodologies began to get increasing public attention. Each had a different combination of old ideas, new ideas, and transmuted old ideas. But they all emphasized close collaboration between the programmer team and business experts; face-to-face communication (as more efficient than written documentation); frequent delivery of new deployable business value; tight, self-organizing teams; and ways to craft the code and the team such that the inevitable requirements churn was not a crisis.
Scrum and RUP are specific software development methods that can enable Agile software development. These methods (and others, such as XP) are not mutually exclusive, and can be combined in many ways to tailor an Agile process suitable for a particular project. This is a good article describing how these methods can be combined.
Agile and RUP grew separately, RUP on the foundation of UML, and now IBM is trying to catch up the agile wave cause there is no [more] big buzz on RUP.
Agile in an umbrella term for methods like XP, Scrum, Crystal, DSDM, FDD,... that share common principles. The Unified Process is a framework that can be used to describe a development process, RUP being one instantiation of UP based on Rational's tools. UP predates most Agile methods and may or may not be considered as Agile. What they have in common is that both Agile methods and UP are Iterative and Incremental Development (IID) methods.
RUP is a comprehensive iterative and incremental process template. You create a "Development Case" that informs you about what process components you will need in your instance of a development process. You then pull the required process components you need from RUP, like picking items from a menu.
"Agile" is an umbrella term that describes the set of processes that are based on the proposition that software development is a learning process rather than a defined process, and that most high-ceremony artifacts and practices impede the learning process.
SCRUM is a specific Agile project management process. It makes no provisions for how to actually design and develop the system being built.