SDLC – Rapid Application Development (RAD) Model

It is also called the Rapid Prototyping Model. The main aim of this model is to reduce development time and cost and yet have the flexibility to incorporate changes. It makes only short team plans and heavy reuses of existing code.

The plans are made for one increment, and the time planned for each iteration is called a time box. After each increment is delivered, the system or the applications becomes more complete. During each iteration, a prototype of the software is first developed is given to the customer for evolution, and this prototype is refined based on customer feedback.

Each iteration or increment enhances the implemented functionality of the application a little. During each iteration:

1. A quick and dirty prototype-style software for some selected functionality is developed.
2. The customer evaluates the prototype and gives his/her feedback.
3. The prototype is refined based on customer feedback.

How does RAD facilitate faster development?

1. RAD achieves the fast creation of working prototypes through the use of specialized tools.
2. These specialized tools usually support the following features:
   • The visual style of development
   • Use of reusable components
   • Use of standard APIs

For which applications is RAD suitable?

1. Customized products developed for one or two customers only.
2. Performance and reliability are not critical.
3. The system can be split into several independent modules.

For which application RAD is unsuitable?

1. Few plugin-in components are available.
2. High performance and reliability are required.
3. No precedence for a similar product exists
4. The system can not be modularized.

Detailed discussion on RAD Model

The plans are made for one increment, and the time planned for each iteration is called a time box. After each increment is delivered, the system or the applications becomes more complete. During each iteration, a prototype of the software is first developed is given to the customer for evolution, and this prototype is refined based on customer feedback.

In the RAD model, the prototype itself is refined to be the actual software. In contrast, in the prototyping model, a derivative of the waterfall model, it is used to get customer feedback, throw away the developed prototype, and start development afresh.

The RAD model achieves faster development and encourages specialized tools; the tools should support visual styles of development like drag and drop. The use of reusable components and the use of standard APIs are something that is supposed to help the software be implemented faster.

In contrast to the waterfall model, this model is very efficient and flexible to incorporate changes because only short-term plans are made. Any change does not require changing all the plans.

Reference

1. Fundamentals of Software Engineering Book & NPTEL Video Lectures by Rajib Mall.

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