Prototype Model

A prototype is a working model that is functionally equivalent to a component of the product. In many instances the client only has a general view of what is expected from the software product. In such a scenario where there is an absence of detailed information regarding the input to the system, the processing needs and the output requirements, A prototype model reflects an attempt to increase the flexibility of the development process by allowing the client to directly interact and experiment with an IbleSoft representative. The developmental process only continues once the client is satisfied with the functioning of the prototype. At this stage the developer clarifies the client’s needs for continued development.

Rapid Application Development

Rapid Application Development (RAD) is an incremental software development process model that emphasizes a very short development cycle [typically 60-90 days]. The RAD model is a high-speed adaptation of the waterfall model, where the result of each cycle is a fully functional system.

RAD is used primarily for information systems applications; the RAD approach encompasses the following phases:

• Business modeling
• Data modeling
• Process modeling
• Application generation
• Testing and turnover

Incremental Model

This model derives its name from the way in which the software is built. More specifically, the model is designed, implemented and tested as a series of incremental builds until the product is finished. A build consists of pieces of code from various modules that interact together to provide a specific function.

At each stage of the Incremental Model a new build is coded and then integrated into the structure, which is tested as a whole. Note that the product is only defined as finished when it satisfies all of its requirements. This model combines the elements of the waterfall model with the iterative philosophy of prototyping at each stage

• The client assigns a value to each build not yet implemented
• IbleSoft estimates cost of developing each build
• The resulting value-to-cost ratio is the criterion used for selecting which build is delivered next 

Essentially the build with the highest value-to-cost ratio is the one that provides the client with the most functionality (value) for the least cost. Using this method IbleSoft’s client has a usable product at every stage of development.

The Spiral Model

The spiral model combines the iterative nature of prototyping with the controlled and systematic aspects of the waterfall model, therein providing the potential for rapid development of incremental versions of the software. In this model the software is developed in a series of incremental releases with the early stages being either paper models or prototypes. Later iterations become increasingly more complete versions of the product.
Depending on the model it may have 3-6 task regions (/framework activities) For example, consider a ‘6-task region’ model as follows:

Depending on the model it may have 3-6 task regions (/framework activities) For example, consider a ‘6-task region’ model as follows:

• The customer communication task – to establish effective communication between developer and customer.
• The planning task – to define resources, time lines and other project related information.
• The risk analysis task – to assess both technical and management risks.
• The engineering task – to build one or more representations of the application.
• The construction and release task– to construct, test, install and provide user support (e.g., documentation and training).
• The customer evaluation task – to obtain customer feedback based on the evaluation of the software representation created during the engineering stage and implemented during the install stage.

The evolutionary process begins at the center position and moves in a clockwise direction. Each traversal of the spiral typically results in a deliverable. For example, the first and second spiral traversals may result in a product specification and a prototype, respectively. Subsequent traversals may then produce more sophisticated versions of the software.

An important distinction between the spiral model and other software models is the explicit consideration of risk. There are no fixed phases such as specification or design phases in the model and it encompasses other process models. For example, prototyping may be used in one spiral to resolve requirement uncertainties and hence reduce risks. This may then be followed by a conventional waterfall development.