"TO BE ENGINEERED" BIRD-VIEW"Specific to Technical" Insight/Terms/Ways to Create the REAL Software Application

The 4+1 Architectural View Model is a well-known method used to describe complex software system architecture. It was introduced by Philippe Kruchten.

Instead of describing a system from only one perspective, the architecture is described using five different views. Each view addresses the concerns of different stakeholders such as developers, system engineers, managers, and end users.

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The Five Views of the 4+1 Model

1. Logical View

The Logical View focuses on the functional design of the system. It describes classes, objects, and their relationships.

Typical diagrams: UML class diagrams, object diagrams.

Customer ➔ Account ➔ Transaction ➔ PaymentService

Purpose: To understand what the system does.

2. Development View (Implementation View)

Describes how the software is organized in the development environment (modules, packages, and libraries).

Application │ ├── User Interface Module ├── Business Logic Module ├── Database Module └── Security Module

Purpose: Helps developers understand the code structure.

3. Process View

Focuses on the runtime behavior, including processes, threads, and concurrency.

• Web server processes
• Database processes
• Background threads

Purpose: Understand system performance and scalability.

4. Physical View (Deployment View)

Describes how software is deployed on hardware infrastructure (servers, networks, and cloud nodes).

Client Device ➔ Web Server ➔ Application Server ➔ Database Server

Purpose: Understand system distribution and hardware needs.

5. Scenario View (The +1)

The Scenario View validates the architecture using real use cases. It shows how the other four views work together.

Example (Login Process): User request ➔ Web server ➔ Auth module ➔ Database ➔ Access granted.

Purpose: Demonstrate how the architecture supports real user interactions.

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Simplified Summary Table

View	Primary Focus
Logical	System functionality & design
Development	Code structure & modules
Process	Runtime behavior & performance
Physical	Hardware deployment & nodes
Scenario	Real-world use cases (The +1)

✅ This model is essential for designing large-scale enterprise systems, cloud platforms, and financial software where multi-stakeholder communication is critical.