4.1.2.1. V-model
The V-model, also called the “verification and validation” model, is a type of software development model that organizes each stage of development and pairs it with a testing stage, resulting in a “V” shape. This model is commonly used in embedded systems development because it ensures quality by catching mistakes early, using the testing stage.
Main phases of the V-model
Requirement analysis - This stage is about gathering information on what the system needs to be doing. All the requirements are written down, with an emphasis on what needs to be done rather than how it needs to be done.
System design - A basic structure of the system is created without going into too much detail.
Architecture design - This stage shows how different parts of the system interact, with diagrams illustrating the relationships between these parts.
Module design - Each component or module is defined in detail, often with diagrams and pseudocode showing exactly how it will work.
Coding - The actual programming happens in this step. Code is written based on all the requirements and system designs from previous steps.
Unit testing - After coding, each module is tested individually to catch any problems or bugs as early as possible.
Integration testing - This stage checks how all the modules function together as a group.
System testing - The entire system is tested as a single unit to ensure the software functions as expected.
User acceptance testing - The system is tested in an environment similar to the user’s to ensure it meets the user’s expectations and needs.
Pros and cons of the V-model
Pros:
Early error detection due to multiple stages of testing, which allow errors to be caught and fixed early.
Clear and easy structure to follow.
Organized documentation produced at each stage.
Cons:
Inflexible structure makes it hard to accommodate significant changes if requirements change too much.
High documentation requirements for each phase, which can slow the process.
Not well-suited for iterative development, as it lacks flexibility for projects that require frequent revisions and an iterative approach.
When to use the V-model
The V-model is best suited for complex projects that require thorough documentation, well-defined requirements, and a rigid structure.
It is ideal for projects that demand high-quality assurance with extensive testing, such as those in automotive, healthcare, and aerospace systems.
Conclusion
The V-model is a structured, step-by-step software development model that emphasizes quality by pairing each development stage with a corresponding testing stage. It is ideal for complex projects with well-defined requirements and a high need for quality. However, it is less suitable for projects that require flexibility or frequent adjustments.