Waterfall model : the provisions of the software life cycle activities for several stages of work in a fixed order and connection, shaped like a waterfall flowing water, finally get software products. The process is the output of an activity that activity as an input, the input of this embodiment using the content of the activity should be completed, and the work to verify the results of the currently active, if the verification, the result of the next entry activities to continue an activity under otherwise modified.
The traditional waterfall model
Advantage of the waterfall model (refer to Baidu Encyclopedia ):
1) provided for the project by checking the waterfall model enumeration phase partitioning.
2) After the completion of the previous phase, just need to focus on subsequent phases.
3) can be applied to the waterfall model in an iterative model.
4) It provides a template that makes the analysis, design, coding, testing, and support the method can have a common guidance on this template.
Waterfall model of shortcomings :
1) divided into various stages completely fixed, a large amount of documents between stage, which greatly increases the workload.
2) Since the development model is linear, the user only until the end of the whole process of development in order to see the results, thus increasing the risk of development.
3) to keep track of the various stages of the project through excessive force completion dates and milestones.
Highlight the shortcomings 4) waterfall model is not suited to the user's needs change.
5) Early errors may have to wait until late in the development and testing stage can be found, then serious consequences.
The traditional waterfall model is too idealistic, only to wait until early mistakes later development can be found, then serious consequences. For the early detection of errors, adding iterative process in the waterfall model. When the later stage of errors found in front of the stage, need to return to an earlier stage in the left side of FIG feedback line, and then come back in front of the correction phase of the product later stage to finish the task.
Waterfall model to join the iterative process