1-1-1 System Requirements Definition Process

[Activities of system requirements definition] (i) Definition of system requirements (ii) Evaluation and review of system requirements

[System requirements]

• • Objectives and scope of computerization (e.g., the targeted work, the targeted
  departments)
• • Functions, capabilities, and life cycle of the system
  – Functions are summarized as functional requirements in system functional specifications. – Capabilities are clarified as performance requirements (e.g., response time, throughput).
• • Business, organizational, and user requirements
  – User work processing procedures, input/output information requirements,

database requirements, operation requirements, and other requirements from the business, organization, and users are clarified. In addition, test requirements to verify these requirements are also defined.

• • Reliability, safety, security, human-factors engineering (i.e., ergonomics), interface,
  operations, and maintenance requirements – Security requirements, operational requirements (including education, training, and others), maintenance requirements (including fault handling and others) are clarified.
• • System configuration requirements
  – Execution environment requirements, peripheral interface requirements, and others are clarified.
• • Design constraints and qualification requirements
  – Design constraints are clarified as design constraint conditions. System configuration requirements can also be design constraints. – Qualification requirements are standards for verifying that a system is of usable quality, and are documented in a specification document of a system qualification test.
• • Development environment
• • Quality, expense, and expected effects
  – Quality is clarified as quality requirements.
• • Migration requirements and validation requirements for system migration

(i) Evaluation of system requirements Defined system requirements are evaluated, in consideration of the criteria of

traceability to acquisition needs, consistency with acquisition needs, testability, feasibility of system architectural design, and feasibility of operation and maintenance. (ii) Implementation of joint review of system requirements A joint review by the development department (i.e., supplier) and stakeholders (i.e., acquirer) is conducted, and agreement is obtained concerning system requirements. In order to deepen mutual understanding, prototypes may be created to verify feasibility, or simulations may be conducted.

[Types of review]

• • Joint review
  This is a review aimed at maintaining among stakeholders a shared understanding of progress toward agreed-upon objectives and shared understanding for the purpose of aiding confirmation that product development satisfies stakeholders.
• • Design review
  This is a review aimed at discovering errors in design documents.
• • Code review
  This is a review aimed at discovering errors (i.e., bugs) in source code (i.e., source programs). It can also be expected to improve the readability of programs.

[Review methods]

• • Walk-through
  This is a review implemented by a creator and multiple concerned parties. It is implemented primarily for the purpose of early discovery of errors.
• • Inspection (software inspection)
  This is a review conducted by a moderator (i.e., a person in charge of implementation). The moderator must bear responsibility for confirmation and correction of errors.