Waterfall Model Vs V-Model

Waterfall Model

Sequential software development process in which progress is seen as flowing steadily downwards from requirements analysis to design, construction, testing and maintenance.

Phases

1. Requirements Specification
2. Design
3. Construction(Coding)
4. Integration
5. Testing and Debugging
6. Installation
7. Maintenance

The Waterfall model maintains that one should move to a phase only when its preceding phase is completed and perfected. To follow this model, one proceeds from one phase to the next in a purely sequential manner.

Advantages

1. Each phase is 100% complete and absolutely correct before proceeding to the next phase. This turns out that time spent early on making sure that requirements and design are absolutely correct will save you much time and effort later.
2. It emphasizes on documentation, requirements documents, design documents and source code. So if new team members or even entirely new teams should be able to familiarize themselves by reading the documents.
3. It follows a simple approach and is more disciplined.
4. It can be suited to software projects that are stapled, with unchanging requirements.

Disadvantages

1. It is impossible to get one phase of a product's life-cycle perfected before moving on to the next phase.
2. Clients may change their requirements after a design is finished, so the entire design must be modified to accomodate the new requirements.

V-Model


The V-Model is a software development process which can be assumed to be the extension of the waterfall model. Instead of moving down in a linear way, the process steps are bent upwards after the coding phase, to form the typical V shape. The V-model demonstrates the relationships between each phase of the development life cycle and its associated phase of testing.

Testing activities like test designing start at the beginning of the project well before coding and therefore saves a huge amount of the project time.

Phases

The verification phase are on the left hand side of the V. Coding phase is at the bottom of the v and the validation phases are on the right hand side of the V.

Verification Phases

1. Requirements Analysis
2. System Design
3. Architecture Design
4. Module Design

Validation Phases

1. Unit Testing
2. Integration Testing
3. System Testing
4. User Acceptance Testing