Proto Type and V-Model

Prototype Model:

•      This is most popular model in IT industry 
•      This model is suitable when the client is not clear about the requirements
•       It is defined as rapidly developed model

Advantages:

• Requirements are defined and extracted from the customer
• Clients environments are conform
• Use of winnings the customer
• To win the customer confidence and to freeze customer requirements

Disadvantages:

• client may stick to this prototype and limit this functionality to it
• it was being built on the cost of the company
• it is not a full model use and throw model
• v model: v stands for verification and validation
• this model defines mapping between software development stages and testing  stages this model is derived from fish model   

 The V- Shaped model

• excellent choice for systems requiring high reliability hospital patient control applications
• all requirements are known up front
• when it can be modified to handle changing requirements beyond analysis 
• solution and technology are known
  v shaped weaknesses
• does not easily handle concurrent events
• does not handle iterations or phases
• does not easily handle dynamic changes in requiments
• Dos not contain risk anaysis activities        

v - shaped Strengths

• Emphasize planning for verfication and validation of the product in early stages of product development
• Each deliverable must be testable
• Project management can track progress by milestones
• Easy to use

Refinement From of V-Model

• V-Model is expensive process for small scale and medium scale organization, Due to this reason, small scale and medium scale Organization are maintaing separate V stands for Verification and Validation,
• Verification done by the developer and QAE
• Test Engineer does Validation

Advantages
the outcome is a qualitive output because each and every Phase well Planned reviewed and Evaluated

Disadvantages
It is very costly model 
Lot of time is consumed due to planning