Introduction The foundations of high quality maintenance Foundation 1: software package quality

1. Presentation 11 Assuring the quality of software maintenance components • Introduction • The foundations of high quality maintenance • Foundation 1: software package quality • Foundation 2: maintenance policy • Pre-maintenance software quality components • Maintenance contract review • Maintenance plan • Maintenance software quality assurance tools • SQA tools for corrective maintenance • SQA tools for functionality improving maintenance • SQA infrastructure components for software maintenance • Managerial SQA tools for software maintenance

2. Software maintenance Corrective maintenance Adaptive maintenance Functionality improvement maintenance Perfective maintenance Preventive maintenance Software maintenance components 54-60% 23-24% 17-22% + User support service

3. User’s difficulties • Software failure • Documentation failure • Incomplete, vague or imprecise documentation • User’s insufficient knowledge

4. Foundation 1: Software package quality Quality factors of high impact on software maintenance

5. Foundation 2: Maintenance policy • Version development policy • Sequential version policy • Tree version policy (branching and new version rules) • Change policy (permissive/balanced)

6. 範 例 在一些年的應用之後，Inventory Perfect這一依據樹狀方針(tree policy)所開發的財產目錄管理套件，已經發展為七版本軟體套件並有這些主要分支：藥房、電子業、醫院、書店、超市、汽車自動修理廠、以及化學工廠。每一分支包含四或五個次分支，差異在軟體模組數目、實行層級或是特定的客戶導向應用。例如，書局版本有下列五個次分支(版本)：連鎖書局、單一書店、進階管理書店、LP連鎖書局的特別版本、CUCB(City University Campus Bookstores)的特別版本。軟體維護小組同時維護軟體套件的總共30個不同版本，每一版本定期依據客戶請求以及小組的技術革新來修正。 維護小組的日常經驗因此包含克服由已經超出軟體本身關連的套件結構所產生的困難：

7. ▓由特定客戶使用的目前版本之模組架構的不適當確 認所引發的不正確的修正。 ▓由稍後證明為不適合整合到客戶套件版本的其他版 本之一個模組，因不正確替換模組所引發的不正確 的修正。 ▓說服客戶來更新他們的軟體套件以加入新開發的模組或是由新版本替換現有版本的努力。緊接著在成功說服客戶更新他們的軟體套件的努力之後，當嘗試整合新開發的模組或是由進階的模組版本替換目前版本之時，所帶來的問題及失敗。 維護小組的領導人時常提到她羨慕她的同行熟人，Inventory Star維護小組的領導人堅持他的公司所開發的軟體套件只提供所有客戶唯一一個綜合版本。 明顯地，Inventory Star所採用的連續方針(sequential policy)需要更少的維護；因為只有一個版本需要被維護，很容易來維持它的品質層級。

8. Pre maintenance SQA components Maintenanace contract review • Customer requirements clarification • Review of alternative approaches to maintenance provision • Review of estimates of required maintenance resources • Review of maintenance services to be provided by subcontractors and/or the customer • Review of maintenance costs estimates

9. Pre maintenance SQA components Preparation of a Maintenanace plan • A list of the contracted maintenance services (external and internal customers) • A description of the maintenance team's organization • A list of maintenance facilities • A list of identified maintenance service risks • A list of required software maintenance procedures and controls • The software maintenance budget

10. SQA tools for corrective maintenance • Mini life cycle SQA tools – Mini testing • Contractor-Subcontractor contract (for outsourcing maintenance services) - Procedures for handling maintenance calls - Full documentation of the service procedures - Availability of records - Certification for the contractor - Quality-related conditions requiring penalties

11. SQA tools for functionality improving maintenance • Project life cycle tools (reviews & testing) Tools are also implemented for large-scale adaptive maintenance tasks.

12. SQA infrastructure components for software maintenance • Maintenance procedure and work instruction • Supporting quality devices • Training and certification of maintenance teams • Preventive and corrective actions • Configuration management • Maintenance documentation and quality record control

13. Managerial SQA tools for software maintenance • Performance controls for corrective maintenance services • Quality metrics for corrective maintenance • Cost of software maintenance quality

14. Cost of software maintenance quality • Cost of prevention • Cost of appraisal • Cost of managerial preparation and control • Cost of internal failure • Cost of external failure • Cost of managerial failure