Incremental Model:

In incremental model the whole requirement is divided into various builds. Multiple development cycles take place here, making the life cycle a “multi-waterfall” cycle. Cycles are divided up into smaller, more easily managed modules. Incremental model is a type of software development model like V-model, Agile model etc.

Each iteration passes through the requirements, design, coding and testing phases. And each subsequent release of the system adds function to the previous release until all designed functionality has been implemented.

Advantages of Incremental model:

• Generates working software quickly and early during the software life cycle.
• This model is more flexible – less costly to change scope and requirements.
• It is easier to test and debug during a smaller iteration.
• In this model customer can respond to each built.
• Lowers initial delivery cost.
• Easier to manage risk because risky pieces are identified and handled during it’d iteration.

Disadvantages of Incremental model:

• Needs good planning and design.
• Needs a clear and complete definition of the whole system before it can be broken down and built incrementally.
• Total cost is higher than waterfall.

Prototype Model:

The basic idea in Prototype model is that instead of freezing the requirements before a design or coding can proceed, a throwaway prototype is built to understand the requirements. This prototype is developed based on the currently known requirements.

Prototype model is a software development model. By using this prototype, the client can get an “actual feel” 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 for which there is no manual process or existing system to help determining the requirements.

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.
• Missing functionality can be identified easily
• Confusing or difficult functions can be identified as Requirements validation, Quick implementation of, incomplete, but functional, application.

Disadvantages of Prototype model:

• Leads to implementing and then repairing way of building systems.
• Practically, this methodology may increase the complexity of the system as scope of the system may expand beyond original plans.
• Incomplete application may cause application not to be used as the full system was designed
• Incomplete or inadequate problem analysis.