Explain incremental model?

The incremental model is proposed by D.L PARNAS. It is basically executed by combining elements of linear sequential model and iterative prototyping model. Incremental development refer to the process of developing to completion only a part of the requirement at a time by selectively developing kinds of the requirements, designing, coding and testing  software that means these needs functions, the software product may be built up incrementally to its final configuration. This approach model shows the product partially to the customer in the starting and slowly at increased functionality to the system. That is why it is known as incremental model.