Entry #10: The 4+1 View Model

In this entry, I will talk about the 4+1 View Model. So, what is it? To learn about it, I watched 2 videos: "The 4+1 Model" and "Six Blind Men. Additionally, I read the article "The Elephant and the Blind Programmers" written by Grady Booch in 2010.

The 4+1 Model is conformed by 5 views and each one represent a view from the software architecture: 

• Logical View: This view shows the parts that comprise the system, as well as their interactions. It represents a set of abstractions and emphasizes classes and objects. The UML diagrams used in this view include Class diagrams, State diagrams, Object diagrams, Sequence diagrams, and Communication diagrams.

• Process View: This view describes a system's processes and shows any communication between those processes. It explores what needs to happen inside the system, as it is very useful when a system will have several simultaneous threads of processes. The UML Activity diagrams represent this view.

• Physical View: This view models the system's execution environment and maps software artifacts onto the hardware that hosts them. The UML Deployment diagrams are used to model this view.

• Development View: This view describes the system's modules/components including packages, sub-systems, and class libraries. It gives a building-block view of the system and helps to manage the system's layers. UML diagrams used in this view are the Component diagrams and Package diagrams.

• Use Case View: This view shows the system's functionality as it captures user goals and scenarios. It offers an outside-world perspective on the system and helps in defining and explaining the structures and functions in the previous four views. The UML Use Case diagrams along with written use cases are used in this view.

The "6 Blind Men" story and "The Elephant and the Blind Programmers" article are related to the 4+1 View Model, because each man/programmer describes a part/section of the animal/architecture, but, as they are guided by their feelings, they tell each other that they are wrong. However, as we can see, they are correct since they are giving characteristics of the animal/architecture.

Article: 

• Booch, G. (2010). The Elephant and the Blind Programmers. Recovered from http://34.212.143.74/s202011/tc3049/the_elephant_and_the_blind_programmers.pdf

Videos:

•  Virtual Training Company. (n.d.). 2.01_The 4 1 Model. Recovered from https://youtu.be/yp2-_YbCuyM
• Phat Phish. (2007). Six Blind Men. Recovered from https://youtu.be/iBqgr5xZLz0