one , Waterfall model :

1, thought : From the production time according to the process to simplify the problem

The function realization and production are separated to facilitate division of labor and cooperation

2, characteristic :

The sequence and dependence between stages are very strong

qa , Deliver qualified documents at each stage , And audit the documents

The idea of postponement

3, advantage :

The foundation of software method is established

Water dependence , Facilitate division of labor and cooperation

Postpone physical implementation , Easy to modify document , With quality assurance

4, shortcoming : Target system meets users late , The later the problem is discovered , The higher the cost of modification , Low success rate , In general 25%

5, Scope of application :

It is suitable for systems with clear system requirements

All kinds of application software development can be used

two , Rapid prototyping model

1. advantage :

Overcome the shortcomings of waterfall model , Better meet the needs of users and reduce the risk of project development due to unclear software requirements .

It is suitable for the development of software system which can't define the requirement in advance .

2. shortcoming :

It is not suitable for the development of large-scale system ( Suitable for the development of small , Flexible system ).

The premise is to have a demonstrative product prototype , Therefore, to a certain extent, it may limit the innovation of developers .

three , Evolution model

Because in the initial stage of project development, people's understanding of software requirements is often not clear enough , Therefore, it is difficult to achieve a successful software development, rework is inevitable , The first time was just in experimental development , Explore the feasibility in the first time , Understand the software requirements , On this basis, the second time ( Limited development ) Make a satisfied product

four , incremental model

1. thought : Starting from the part , First, build an incomplete system and test it , Further improve the system

2. advantage : Developers and users are always involved in the process of development , If you have any questions, you can modify them at any time , Meet customer needs

3. Scope of application : It is suitable for the development of knowledge software system

4. characteristic : The overall structure is not as clear as waterfall

The document of software is not as strict as waterfall

Long cycle , High cost

Meet users quickly , High development efficiency

five , Spiral model

Rotate along the helix , Four quadrants express four aspects respectively

Designated plan : Define software goals , Select the implementation plan , Clarify the constraints of project development

risk analysis : Analysis of options , Consider how to identify and eliminate risks

Implementation project : Implement software development

Customer evaluation : Evaluate development work , Proposed amendments

six , Fountain model

characteristic : iteration

repeat . evolution , No gap

seven , Transformation type :

Have strict mathematical theory and formal technical support , But it is still in the research and experimental stage , Not practical