BCS/CER/IS/DIP/SE1/ Prototype Model

Prototype Model

Prototyping is a working model of a real system. There are two types of prototypes. The basic idea here is that instead of freezing the requirements before a design or coding can proceed, 

• Throw-away prototype
• Evolutionary Prototype 

Throw-away prototype
Model is use to gather requirements, after gathering requirements development start from the beginning. 

Evolutionary Prototype
Model is use to get the user feedback and finalize the model and deliver the system

Throwaway prototype is built to understand the requirements. This prototype is developed based on the currently known requirements. By using this prototype, the client can get a “what users really want” of the system, since the interactions with prototype can enable the client to better understand the requirements of the desired system.  Prototyping is an attractive idea for complicated and large systems.

Advantages of Prototype model:

• Users are actively involved in the development
• Since in this methodology a working model of the system is provided, the users get a better understanding of the system being developed.
• Errors can be detected much earlier.
• Quicker user feedback is available leading to better solutions.
• Confusing or difficult functions can be identified
• Requirements validation, Quick implementation of, incomplete, but functional, application.

Disadvantages of Prototype model:

• Leads to implementing and then repairing way of building systems.
• Increase the complexity of the system as scope of the system may expand beyond original plans.

BCS/Dip/SE1/ Waterfall Model

Waterfall Model

The waterfall model is a popular version of the systems development life cycle model for software engineering. Often considered the classic approach to the systems development life cycle, the waterfall model describes a development method that is linear and sequential. Waterfall development has distinct goals for each phase of development. Imagine a waterfall on the cliff of a steep mountain. Once the water has flowed over the edge of the cliff and has begun its journey down the side of the mountain, it cannot turn back. It is the same with waterfall development. Once a phase of development is completed, the development proceeds to the next phase and there is no turning back.

Advantages

• Simple and easy to understand and use
• Easy to manage due to the rigidity of the model . 
• each phase has specific deliverable and a review process.
• Phases are processed and completed one at time.
• Works well for smaller projects where requirements are very well understood.