软件工程第四版第2章.ppt

Contents 2.1 The Meaning of Process 2.2 Software Process Models 2.3 Tools and Techniques for Process Modeling 2.4 Practical Process Modeling 2.5 Information System Example 2.6 Real Time Example 2.7 What this Chapter Means for You Chapter 2 Objectives What we mean by a “process” Software development products, processes, and resources Several models of the software development process Tools and techniques for process modeling 2.1 The Meaning of Process A process: a series of steps involving activities, constrains, and resources that produce an intended ouput of some kind A process involves a set of tools and techniques 2.1 The Meaning of ProcessProcess Characteristics Prescribes all major process activities Uses resources, subject to set of constraints (such as schedule) Produces intermediate and final products May be composed of subprocesses with hierarchy or links Each process activity has entry and exit criteria Activities are organized in sequence, so timing is clear Each process has guiding principles, including goals of each activity Constraints may apply to an activity, resource or product 2.1 The Meaning of ProcessThe Importance of Processes Impose consistency and structure on a set of activities Guide us to understand, control, examine, and improve the activities Enable us to capture our experiences and pass them along 2.2 Software Process ModelsReasons for Modeling a Process To form a common understanding To find inconsistencies, redundancies, omissions To find and evaluate appropriate activities for reaching process goals To tailor a general process for a particular situation in which it will be used 2.2 Software Process ModelsSoftware Life Cycle When a process involves building a software, the process may be referred to as software life cycle Requirements analysis and definition System (architecture) design Program (detailed/procedural) design Writing programs (coding/implementation) Testing: unit, integration, system System delivery