The V Model
The V model is a modified version of the Waterfall method. As opposed to the Waterfall method, this one was not designed in a linear axis; instead the stages turn back upwards after the coding phase is done so that it makes a V shape and hence the name – V Model. It was put forth by Paul E. Brook in 1986. Let’s look at the different stages, test processes, techniques, advantages and disadvantages of this method.
About The Cyclic Phases
The V Model is in contrast to the Waterfall method in more than one way. This developmental process is balanced and relies on the verification from the previous steps before proceeding forward. So the cycle of the model has been divided into several phases and each one is supposed to yield a predefined product.
When the product from one phase has reached completion, it will then form the basis for the next phase. This signifies the importance of verification in this model. Similar to the waterfall model, one progresses to the next step when the previous one has been completed. However in the V Model, the product from every phase needs to be checked and approved before moving forward.
This way of verification continues for all the stages and with subsequent phases, one receives a new base of an approved product which instills more confident in the project.
The Various Stages of the V model
1. Requirement Analysis
This is the first step in the verification process. It is in here that the project and its function is decided. So a lot of brainstorming and documentation reveals what all will be required to produce that program or product. During this stage the employees are not going to discuss how it is going to be built; it is going to be a generalized discussion and a user requirement document is put forth. This document will carry information regarding the function of the system, performance, security, data, interface etc.
This document is required by the business analysts to convey the function of the system to the users. So it will merely be a guideline.
2. System Design
Like the name of the phase suggests, here the possible design of the product is formulated. It is formulated after keeping in mind the requirement notes. While following the documents, if there is something that doesn’t fit right in the design, then the user is made aware of it and changes are accordingly planned. Diagrams and data dictionary is also produced here.
3. Architecture Design
The architecture design, also known as the computer architecture design or the software design should realize the modules and the functionality of the modules which have to be incorporated.
4. Module Design
In the module design, the architectural design is again broken up into sub units so that they can be studied and explained separately. The units are called modules. The modules can separately be decoded by the programmer.
The Validation Phases of the V model
1. Unit Testing
A unit in the programming system is the smallest part which can be tested. In this phase each of these units are tested.
2. Integration Testing or Interface Testing
In this phase the separate entities will be tested together to find out the flaws in the interfaces.
3. System Testing
After the previous stage of interface testing, in this phase it is checked if the system meets the requirements that have been specified for this integrated product.
4. Acceptance Testing
In the acceptance test, the integrated product is put against the requirement documents to see if it fulfills all the requirements.
5. Release Testing
It is in here that judgment has to be made if the product or software which is created is suitable for the organization.
Advantages of the V Model
The biggest advantage of using the V Model is that unlike the Waterfall model and the aorta life cycle method, every stage is tested.
Disadvantages of the V Model
It assumes that the requirements do not change.
The design is not authenticated.
The Requirements are not verified.
At each stage there is a potential of errors. The first testing is done after the design of modules which is very late and costs a lot.