Software Engineering - Old Questions

4. Explain the concept of incremental model with example.

In an incremental model, customers identify, in outline, the services to be provided by the system. They identify which of the services are most important and which are least important to them. A number of delivery increments are then defined, with each increment providing a sub-set of the system functionality. The allocation of services to increments depends on the service priority with the highest priority services delivered first.

Once the system increments have been identified, the requirements for the services to be delivered in the first increment are defined in detail, and that increment is developed. During development, further requirements analysis for later increments can take place, but requirements changes for the current increment are not accepted.

Once increment is completed and delivered, customers can put it into services they can experiment with the system that helps to clarify their requirements for later increments and for later versions of the current increment. As new increments are completed, they are integrated with existing increments so that the system functionality improves each delivered increment. The common services may be implemented early in the process or may be implemented incrementally as functionality is required by an increment.

(In incremental model, rather than deliver the system as a single delivery, the development and delivery is broken down into increments with each increment delivering part of the required functionality. User requirements are prioritised and the highest priority requirements are included in early increments. Once the development of an increment is started, the requirements are frozen though requirements for later increments can continue to evolve).