要寫好一份'軟體需求規格文件' (SRS) 不容易。 '使用者需求'是它的Input，'軟體設計文件' 是它的Output。
[User Requirements] --> [SRS] --> [SW Design (High Level Design + Detailed Level Design)]
什麼樣的SRS才是好的? 下列四點是個不錯的判斷依據:
1. 提供回饋給user。最好的回饋方式就是讓User看到! 比如UI、Output files, Tools
2. 用軟體的觀點來看問題，把問題分解成幾個SW components。What (SW components, Tools) should be enhanced/changed/updated/removed/created...
3. SRS是SW design 的Input。SRS 只需定義'規格' (What)，它是一份合約。實作方式則定義在SW Design (How)。
4. SRS 必須用'外顯'、'可量測' 的角度來撰寫，好讓Tester判斷正確性。
看了許多的 SRS, 節錄出下列幾個重要方向:
Functional requirement: 定義系統要做的事 (What the system does)
• Business Rules
• External Interfaces (ex: UI, output files...)
• Audit Tracking (ex: Logging)
• Transaction corrections, adjustments and cancellations
• Administrative functions
• Authentication
• Authorization levels
• Certification Requirements
• Reporting Requirements
• Historical Data
• Legal or Regulatory Requirements
Non-functional requirements: 定義系統的能力 (What the system's capability - the power to do it)
• Reliability - 可以依據既定規格而持續運行的能力
• Serviceability
• Availability
• Performance – for example Response Time, Throughput, Utilization, Static Volumetric
• Scalability - To handle a growing amount of work (系統處理工作量的成長)
• Capacity - 系統可以產出(或提供服務)的最大量
• Recoverability
• Maintainability: 維持原有的形式，萬一發生錯誤也可以回復到原有的形式
• Security
• Regulatory
• Manageability
• Environmental
• Data Integrity
• Usability
• Interoperability
[User Requirements] --> [SRS] --> [SW Design (High Level Design + Detailed Level Design)]
什麼樣的SRS才是好的? 下列四點是個不錯的判斷依據:
1. 提供回饋給user。最好的回饋方式就是讓User看到! 比如UI、Output files, Tools
2. 用軟體的觀點來看問題，把問題分解成幾個SW components。What (SW components, Tools) should be enhanced/changed/updated/removed/created...
3. SRS是SW design 的Input。SRS 只需定義'規格' (What)，它是一份合約。實作方式則定義在SW Design (How)。
4. SRS 必須用'外顯'、'可量測' 的角度來撰寫，好讓Tester判斷正確性。
看了許多的 SRS, 節錄出下列幾個重要方向:
Functional requirement: 定義系統要做的事 (What the system does)
• Business Rules
• External Interfaces (ex: UI, output files...)
• Audit Tracking (ex: Logging)
• Transaction corrections, adjustments and cancellations
• Administrative functions
• Authentication
• Authorization levels
• Certification Requirements
• Reporting Requirements
• Historical Data
• Legal or Regulatory Requirements
Non-functional requirements: 定義系統的能力 (What the system's capability - the power to do it)
• Reliability - 可以依據既定規格而持續運行的能力
• Serviceability
• Availability
• Performance – for example Response Time, Throughput, Utilization, Static Volumetric
• Scalability - To handle a growing amount of work (系統處理工作量的成長)
• Capacity - 系統可以產出(或提供服務)的最大量
• Recoverability
• Maintainability: 維持原有的形式，萬一發生錯誤也可以回復到原有的形式
• Security
• Regulatory
• Manageability
• Environmental
• Data Integrity
• Usability
• Interoperability
Non-functional 影響層面有:
- Reliability: Improvement in number of hits [hits/ syst yr] (Hit 次數)
- Serviceability: Improvement on Maintenance and in MTTR (diagnostics, access, repair and/or recovery) repairing of system [hrs] (維修, 回復 時數)
- Availability: Improvement in hours of downtime both USD (Unscheduled) as well as SD (Scheduled) [hrs/syst yr] (Downtime 時數)
- Manufacturability: Improvement in CT (Cycle Time) or A-time in production [hrs/ syst]
- Safety: Improvement of probability of incidents occurring
- Usability: Functional improvement of machine for operator
- Machine Performance: Non-functional improvement of customer requirements
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