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Tracing. CS4310 Fall 2012. What is Requirements Traceability?. The ability to describe and follow the life of a requirement throughout the system lifecycle, in both forward and backward directions. DoD Std 21267A.
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Tracing CS4310 Fall 2012
What is Requirements Traceability? • The ability to describe and follow the life of a requirement throughout the system lifecycle, in both forward and backward directions.
DoD Std 21267A • The document in question contains or implements all applicable stipulations of the predecessor document • A given term, acronym, or abbreviation means the same thing in all documents • A given item or concept is referred to by the same name or description in the documents • All material in the successor document has its basis in the predecessor document, that is no untraceable material has been introduced • The two documents do not contradict one another
Artifacts • Pairs: What artifacts can be used for tracing, 3 minutes. Think of the following stages: • Elicitation • Specification • Construction
Artifacts • Elicitation • Interview report • Requirement specification • Memos, conversations, email • Specification • SRS • Construction • Design models • Code • Test plan
Tracing • An SRS is traceable if it is written to facilitate referencing individual requirements.
Tracing • An SRS is traceable if it is written to facilitate referencing individual requirements. • Take some feature of design and map it through the SRS to the source of the requirement.
Tracing • An SRS is traceable if it is written to facilitate referencing individual requirements. • Take some feature of design and map it through the SRS to the source of the requirement. • How: careful and complete numbering of the sections and elements of the SRS.
Tracing • An SRS is traceable if it is written to facilitate referencing individual requirements. • Take some feature of design and map it through the SRS to the source of the requirement. • How: careful and complete numbering of the sections and elements of the SRS. • An SRS is traced if a flow up path can be identified between a requirement in the SRS and system level requirements in a statement of need or some other artifact (email, meeting notes, etc).
Tracing • For any feature of the deliverable, • Trace to its initial source • Trace to its ultimate implementation
Types of tracing • Pairs: Name four types of tracing
Types of tracing • A. Forward from requirements • B. Backward to requirements • C. Forward to requirements • D. Backward from requirements • 2. • 3. 4. • C. A. • D. B. CONSTRUCTION ARTIFACTS ELICITATION ARTIFACTS SRS
Benefits • V&V • Align business needs with software being developed • Reduce risk by capturing knowledge vital to project success • Determine impact of change to requirements • Support process improvement • Conflict detection and resolution
Tracing helps QA/QC • everything must be verified • goals of verification • results may not be binary • verification may be objective or subjective
When? • Continuously. • Initially • Interview, prototype • Elaboration • Architecture • Construction • Unit testing, verification • Maintenance
Secrets • Trace continuously • Understand why traceability is important • Have a strategy
Problems • It’s hard to do: manual links • Benefits frequently not seen until later • Difficult to measure return on investment
Requirements Management • Requirements management is the set of activities that help the project team to identify, control, and track requirements and changes to requirements at any time as the project proceeds. • Requirements management begins with the identification of requirements.
Requirements Management- Identification • Each requirement is assigned a unique identify that might take the form: • <artifact-identifier><internal-identifier> • artifact-identifier: code that identifies the artifact. • e.g., FR for Feasibility Report, SRS for Software Requirements Specification, IR for Interview Report, M11-10-03 for Memoranda dated 11/10/2005. • internal-identifier: code that references a section, a requirements number, or some other part of the document. • The internal identifier should allow someone to locate the information easily.
Traceability Tables • Possible types of traceability tables include: • Features traceability table • Source traceability table • Dependency traceability table • Subsystem traceability table • Interface traceability table
Traceability Tables • Features traceability table: • Shows how requirements relate to important customer observable system/product features. • Source traceability table: • Identifies the source of each requirement. • Dependency traceability table: • Indicates how requirements are related to one another.
Traceability Tables • Subsystem traceability table: • Categorizes requirements by the subsystem(s) that they govern. • Interface traceability table: • Shows how requirements related to both internal and external system interfaces.
Source Traceability Sources SRS Requirements