1. R & D model
1.1. Waterfall model
1. Stage:
Planning (project plan), requirements (requirement specification SRS), design (outline design HLD and detailed design LLD), development (code and use cases), testing (execution testing), maintenance (product maintenance)
2. Features:
Linear, serial, and risk-free control capabilities. The core idea is to simplify the problem according to the process, separate the realization of the function from the design, and facilitate the division of labor and collaboration.
3. Scope of application:
Small project and clear requirements
4. Advantages:
Simple and efficient (requires the product to go online immediately, the first time to ensure operation, and other time to do so)
5. Disadvantages:
The test was intervened late, the personnel were idle, and the follow-up work could not keep up
There is very little feedback between the various stages of the project
The results can only be seen later in the project declaration cycle
Track various project phases with excessive mandatory completion dates and milestones
1.2. Spiral model
Based on the risk management model, high risk is given priority, and the requirements on risk management personnel are relatively high. Combining basic waterfall models and evolutionary / incremental prototyping methods
1. Differences:
There is an alternative, which is a parallel collection of multiple waterfall models, fully considering the risk
2. Advantages:
Fully consider the risks, strong wind resistance
3. Disadvantages:
The cost is too high and requires the participation of professional risk analysis experts
2. Test the model
2.1. V model
1. Stage:
Requirements analysis, summary design, detailed design, coding, unit testing, integration testing, system testing, acceptance testing
2. Introduction:
Variations of waterfall models, reflecting the relationship between testing activities and analysis and design
From left to right, the basic development process and test behavior are described. The value is that it clearly indicates the different stages in the test process and clearly describes the corresponding relationship between each stage of testing and development.
3. Limitations:
Taking testing as the last activity after coding, does not meet the "3 early" principle of software testing, and errors generated in the early stage such as requirements analysis cannot be discovered until the later acceptance test
2.2. W model
On the basis of the V model, synchronous testing at the development stage is added to form the W model. Simultaneous testing and development is conducive to early detection of problems
1. Limitations:
Think of development activities as serial activities from the beginning of requirements to the end of coding. Only after the completion of the previous stage, the activities of the next stage begin. It cannot support iteration, spontaneity and change adjustment