Evolutionary requirements

1
Evolutionary requirements

• Larman chapter 5

2
Definitions

• Requirements are capabilities and conditions to
  which the system and more broadly, the project
  must conform
• Requirements analysis is the discipline of
  finding, communicating and remembering what is
  really needed for the system
• Manage requirements is a systematic approach to
  finding, documenting, organizing and tracking the
  changing requirements of a system

3
Iterative refinement of requirements

• In early iterations much work is done to analyze
  and specify requirements
• In later iterations requirements will become more
  stable

4
Types of requirements

• FURPS model
• Functional features, capabilities, security
• Usability human factors, help, documentation
• Reliability frequency of failures,
  recoverability, predictability
• Performance response times, throughput,
  accuracy
• Supportability adaptability, maintainability,
  internationalization

5
Types of requirements

• in FURPS (everything else)
• Implementation resource limitations, languages
  and tools, hardware
• Interface constraints imposed by interfacing
  with external systems
• Operations system management in its operational
  setting
• Legal licensing and so forth

6
Alternative classification

• Functional requirements
• Non-functional requirements

7
Requirements organized in UP artifacts

• Use-case model
• Typical scenarios
• Functional requirements
• Supplementary specifications
• non-functional requirements
• features
• Vision document
• Scope of the project
• Business case
• High level requirements
• (Business rules
• Domain rules)