Several major development model differences and linkages

The teacher finished a few development models, I found that the original development of a software is also a step can be found, not the kind of side-to-side change mode. I have compiled a few typical development models in view of the lessons learned and the online browsing information.

A typical development model is:

1. Waterfall model (Watermodel);

2. Incremental model, or evolutionary, iterative (incremental model);

3. Prototype models (prototype model);

4. Helical models (spiral model);

5. Fountain models (fountain model);

6. Intelligent models (intelligent model);

7. Mixed models (hybrid model).

Second, Introduction

(1) Edge-to-side modification model: only applicable to a small amount of code software, after all, this model has no format description, and has not been designed, the software with the customer needs to be modified again and again. A model that is largely not considered.

(2) Waterfall Model: 1970 The life cycle of waterfall model is divided into 6 basic activities such as planning, requirement analysis, software design, programming, software testing and operation maintenance. Later the evolution of the "V"-shaped structure of the waterfall model.

Features: Emphasize the role of the document, and require each stage of self-study verification.

Shortcomings:a-> to write a large number of documents, consuming a lot of energy;

B-> users to see and experience the software at the end of the development cycle, thereby increasing the risk of development;

Early errors in c-> may not be discovered until late in development, leading to significant consequences.

(3) Rapid prototyping model: to build a rapid prototype, the implementation of the future user or customer-to-system interaction, through customer and user feedback to further refine the development of software requirements. Gradually meet the requirements of customers. This process repeats after each incremental release until the final product is produced.

Features: Overcome the shortcomings of waterfall model, reduce the development risk of software requirements.

(4) Incremental model: As with building a building, the software needs to be built step-by-step. The first increment is the core of the software, and the next incremental development plan is formed after the evaluation.

Features: The software as a series of incremental components (a subset of software) to design, implementation, integration and testing, each component is a variety of modules formed by the interaction of providing a specific function of the code fragment composition.

Disadvantage:a-> design software should have an open architecture;

B-> is prone to degenerate into a model of edge modification, so that the control of software development process loses its entirety.

(5) Spiral Model: It is a combination of rapid prototyping model and waterfall model, emphasizing the risk analysis neglected by other models, especially for large and complex systems.

Features: Risk-driven, emphasis on options and constraints to support software reuse, helping to integrate software quality into product development as a special goal.

Disadvantage:a-> It is not easy for customers to accept and believe this risk analysis. Often applies to internal large-scale software development.

B-> greatly affects the profitability of the project and is extremely detrimental to the project and is therefore suitable for large-scale software projects.

C-> requires software developers to be adept at looking for possible risks and analyzing risks accurately, otherwise they will pose greater risk.

(6) Evolutionary model: mainly for software development which can not define the requirement completely beforehand. Users can give the core requirements of the system to be developed, and when the core requirements are realized, they can effectively provide feedback to support the final design and implementation of the system.

Features: The evolutionary model requires developers to be able to break down the product requirements of a project into different groups for batch cycle development. In fact, this model can be seen as multiple "waterfall models" of repeated executions.

(7) Fountain Model: (Object-oriented lifetime model, OO model): Fountain model compared with the traditional structured lifetime, it has more increment and iterative properties, each stage of the lifetime can overlap and repeat multiple times, and the lifetime of the project can be embedded in the whole life period. Like water spray can fall down, can fall in the middle, can also fall on the bottom.

(8) Intelligent model (four-generation technology (4GL)): The intelligent model has a set of tools (such as data query, report generation, data processing, screen definition, code generation, high-level graphics capabilities and spreadsheets, etc.), each of which enables developers to define certain features of the software at a high level, And the developer-defined software automatically becomes the source code.

Development of small and medium-sized applications that are limited to transaction information systems.

(9) Mixed model: Also called process development model, or meta-model. Combine several different models into a hybrid model that allows a project to evolve along the most efficient path, which is the process development model (or hybrid model).

Third, finally do a summary

    Models                             Benefits                                                                             Disadvantages

A-> Waterfall Model Document-driven system may not meet customer needs
B-> Rapid prototyping model focus on meeting customer needs may lead to poor system design, low efficiency and difficult maintenance
C-> Incremental Model development early feedback timely, easy to maintain open architecture may be poorly designed and inefficient
d-> Spiral Model risk-driven risk analysts need to be experienced and fully trained

For more information, please refer to: http://blog.163.com/[email protected]/blog/static/98695674201222510532566/;

Several major development model differences and linkages