Prototype Model Lecture-4

4.1 What is Prototyping? Prototyping is the process of quickly putting together a working model (a prototype) in order to test various aspects of a design, illustrate ideas or features and gather early user feedback. Prototyping is often treated as an integral part of the system design process, where it is believed to reduce project risk and cost. The Prototyping model suggests that before carrying out development of actual software, a working prototype of the system is built.

4.2 Prototyping Model Often one or more prototypes are made in a process of incremental development where each prototype is influenced by the performance of previous designs, in this way problems or deficiencies in design can be corrected. When the prototype is sufficiently refined and meets the functionality, robustness, manufacturability and other design goals, the product is ready for production.

4.3 What is a Prototype? A prototype is a toy implementation of a system having: limited functional capabilities, low reliability, inefficient performance. An important purpose for the use of prototype is: To illustrate the input data formats, messages, reports, and The interactive dialog to the customer

4.4 Why Prototyping? A developed prototype can help engineers: To critically examine technical issues associated with product development: response time of a hardware controller, efficiency of a sorting algorithm, etc. The next reason for developing a prototype is: it is impossible to ``get it right'' the first time, we must plan to throw away the first product if we want to develop a good product.

4.5 How prototyping model is built? Start with approximate requirements. Carry out a quick design. Built a prototype: The developed prototype is submitted to the customer for his evaluation: Based on the user feedback, requirements are refined. This cycle continues until the user approves the prototype. The actual system is developed using the iterative waterfall approach.

4.6 Prototyping Process Req. gathering Quick design Iterative waterfall model Refine Req. Built prototype Evaluate prototype Accepted by the customer Design Implementation Test Maintenance

4.7 Advantages of prototyping Reduced time and costs: changes cost exponentially more to implement as they are detected later in development, the early determination of what the user really wants can result in faster and less expensive software Improved and increased user involvement Prototyping requires user involvement and allows them to see and interact with a prototype allowing them to provide better and more complete feedback and specifications

4.8 Disadvantages of prototyping Insufficient analysis Excessive development time of the prototype Expense of implementing prototyping User confusion of prototype and finished system

4.9 When to use Prototype Model? The prototyping model is suitable for: Projects for which either the user requirements or the underlying technical aspects are not well understood. Especially popular for development of the user- interface part of the project.