软件工程Chapter 02 software process.ppt

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Requirements engineering process There are four main activities in the requirements engineering process: Feasibility study An estimate is made of whether the identified user needs may be satisfied using current software and hardware technologies. Requirements elicitation and analysis is the process of deriving the system requirements through observation of existing systems, discussions with potential users and procurers, task analysis, and so on. Requirements specification is the activity of translating the information gathered during the analysis activity into a document that defines a set of requirements. Requirements validation This activity checks the requirements for realism, consistency, and completeness. Requirements engineering process A software design is a description of the structure of the software to be implemented, the data models and structures used by the system, the interfaces between system components and, sometimes, the algorithms used. The implementation stage of software development is the process of converting a system specification into an executable system. Software design and implementation A general model of the design process A general model of the design process The diagram suggests that the stages of the design process are sequential. In fact, design process activities are interleaved. Four activities that may be part of the design process for information systems: Architectural design, where you identify the overall structure of the system, the principal components (sub-systems or modules), their relationships, and how they are distributed. Interface design, where you define the interfaces between system components. Component design, where you take each system component and design how it will operate. Database design, where you design the system data structures and how these are to be represented in a database. 2.2.3 Software validation Software validation or, more gener