Shaoxing predecessor CMMI4 level model is the difference between CMMI model SW-CMM and SE-CMM, the former is what we refer to CMM. The main difference between CMMI and SW-CMM is covering many areas; so far include the following four areas: (1) software engineering (SW-CMM) is the object of software engineering software system development activities, requirements for software development, operation , maintenance activities systematic, institutionalized, to quantify. (2) Systems Engineering (SE-CMM) systems engineering object is to develop a full set of system activity, may or may not include software. Core systems engineering is the customer's needs, expectations, and constraints into product solutions, and implementation of a solution to support the entire process. (3) integrated product and process development (IPPD-CMM) integrated product and process development is defined as the product life cycle, through co-operation of all stakeholders, using a systematic process to better meet customer needs, expectations and requirements. If the project or enterprise select IPPD process, you need to use the model for all the IPPD-related practices. Content (4) Procurement (SS-CMM) purchase behavior applies to suppliers of the success of the project who play a key role in the project. The main contents include: Identify and evaluate the potential source of the product to determine the need to purchase the product target suppliers, monitor and analyze vendor implementation process, evaluate suppliers and the work product supply agreement and supply relationships make the appropriate adjustments. In the above module, companies can choose software engineering, or systems engineering, you can also choose. Integrated product and process development and procurement primarily with software engineering and systems engineering content usage. For example, pure software companies can choose the content CMMI software engineering; equipment manufacturers can select systems engineering and procurement; integrated companies can choose software engineering, systems engineering and integrated product and process development. CMMI Most of the content is applicable to different areas, but there will be significant differences in the implementation, so that the model provides a "different areas of application Detailed." CMM-based activities, metrics and waterfalls orderly process, activity-based management practices have a very close contact, more suitable for waterfall development process. CMM and CMMI relatively more step to support the iterative development process and the use of economic incentives to promote the organization based on the results of the method: the development of a business case, concept and prototype programs; Hounaruji line structure refinement, can release the final release scheduled for the site. Although based on CMMI retains activity, which does a lot of integrated within the software industry's best modern practices, so it is largely played down the idea of ??contact and waterfalls. In the CMMI model while retaining the CMM-stage model, based on the emergence of a continuous model, which can help customers to an organization and the organization of a more objective and comprehensive understanding of its process maturity. Meanwhile, the continuous use of the model can give an organization when making process improvements to bring greater autonomy, no longer the same as CMM, severely restricted class. This benefit is improved flexibility and objectivity strong, weakness is the lack of guidance, an organization may lack the proper understanding of the dependencies between the key process areas and the implementation of a one-sided process, resulting in some processes become castles in the air, the lack of other processes support. Two manifestations (continuous and phase) from the process area covered by them is no different, except that the organization of the process area and the maturity (capacity) level determination methods. CMMI model than CMM further strengthen the focus on demand. In the CMM, the only requirement on demand management which is a key process areas, that is, emphasize the need for quality management, and how to obtain the demand is not made clear requirements. CMMI model in stages, three have a separate key process area called the demand for the development, made great demands on how to get the requirements and methods. CMMI model for engineering activities, which must be strengthened. In the CMM, only three of the software product engineering and peer review of two key process areas are closely related with the engineering process, but in CMMI, will demand the development, verification, validation, technology solutions, product integration of these projects process activities as a separate domain key process requirements, which in practice put forward higher requirements for the project and more specific guidance. CMMI also emphasizes risk management. Unlike in the CMM to disperse risk management in the project plan and project tracking and monitoring carried out requirements, CMMI3 class singled out in a separate key process area is called risk management.