Kiến trúc máy tính và hợp ngữ - Chapter 5: Requirement management

Requirement Management Requirement Management is a process to organize and manage Requirement to ensure all requirements are satisfactorily implemented and accepted  Proposing changes  Analyzing impact  Making decisions  Updating requirements documents  Updates plans  Measuring requirements volatility  Defining a version identification scheme  Identifying requirements document versions  Identifying individual requirement versions  Defining a possible requirement statuses  Recording the status of each requirement  Reporting the status distribution of all requirements  Defining links to other requirements  Defining links to other system elements Change control Version control Requirements status tracking Requirements tracing Requirements Management Requirements errors, conflicts, and inconsistencies May be detected at any phase (when requirements are analyzed, specified, validated, or implemented) Evolving customer/user knowledge of the system When the requirements are developed, customers/users simultaneously develop a better understanding of what they really need Technical, schedule, or cost problems Difficult to plan and know everything in advance We may have to revisit the list of requirements and adapt it to the current situation Changing customer priorities, new needs Requirements traceability refers to the ability to describe and follow the life of a requirement Traceability Provide a traceability analysis or matrix which links requirements, design specifications, and validation. Providing the links necessary for determining where information is located. Traceability It demonstrates the relationship between design inputs and design outputs It ensures that design is based on predecessor, established requirements It helps ensure that design specifications are appropriately verified, that functional requirements are appropriately validated Traceability Requirement Depends-on R1 R3, R4 R2 R5, R6 R3 R4, R5 R4 R2 R5 R6 Risk Assessment (Initial and Ongoing Activities) Trace potential risks to their specific cause Trace identified mitigations to the risk Trace specific causes of software-related risk to their location in the software Requirements Analysis and Specification Trace Software Requirements to User Requirements Trace Child Requirements to their Parent Requirement Trace Software Requirements to hardware, user, operator and software interface requirements Design Trace Architectural Design to Software Requirements Trace Design Interfaces to hardware, user, operator and software interface requirements Trace Detailed Design to Architectural Design Source Code Analysis Trace Source Code to Detailed Design Specifications Trace unit tests to Source Code and to Design Specifications Integration Test Trace integration tests to Architectural Design System Test Trace system tests to Software Requirement Specifications Use a variety of test types Design test cases to address concerns such as robustness, stress, security, recovery, usability, etc. Use traceability to assure that the necessary level of coverage is achieved The requirements baseline is the set of functional and nonfunctional requirements that the development team has committed to implement in a specific release. At the time the requirements are baseline – typically following formal review and approval – they are placed under configuration management. During project planning, a PM decides which process is to be followed for handling change requests. Because change requests have cost implications, it is necessary to have a clear agreement. Some requirements problem is identified Could come from an analysis of the requirements, new customer needs, or operational problems with the system Log the changes in CR form The proposed changes are analysed Perform an impact analysis on the work products. Estimate the effort needed for the change requests. Re-estimate the delivery schedule. Perform a cumulative cost impact analysis. Review the impact with senior management if thresholds are exceeded. Obtain customer sign-off. The change is implemented: Rework work products through its life cycle