1. SE513 Software Quality Assurance Lecture02: Software Quality Factors SE513 Software Quality Assurance Lecture02: Software Quality Factors Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

2. 2 The need for comprehensive software quality requirements Classification of requirements into software quality factors Product operation factors Product revision factors Product transition factors Alternative models of software quality factors Who is interested in defining quality requirements? Software compliance with quality factors Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

3. 3 The need for comprehensive SQ Requirements “our new sales information system seems okay, the invoices are correct, the inventory records are correct, the discounts granted to our clients exactly follow our very complicated discount policy, but our new sales information system frequently fails, usually at least twice a day, each time for twenty minutes or more…” “Just half a year ago, we launched our new product – the radar detector. The firmware RD-8.1., embedded in this product, seems to be the cause for its success. But when we began planning the development of a European version of the product, we found out that though the products will be almost similar; our software development department needs to develop new firmware; almost all the design and programming will be new” Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

4. 4 “But’s …” All the software project fulfilled the basic requirements All the software project suffered from poor performance in important areas The cause for the poor performance: – Lack of predefined requirements to cover these important aspects of the software’s functionality  need for a comprehensive definition of requirements Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

5. 5 Software quality factors Product operation factors Product revision factors Product transition factors Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

6. 6 Correctness Reliability Efficiency Integrity Usability Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

7. 7 Maintainability Flexibility Testability Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

8. 8 Portability Reusability Interoperability Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

9. 9 Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

10. 10 Galin, SQA from Theory to Implementation @Pearson Education Limited 2004

11. Review questions Galin, SQA from Theory to Implementation @Pearson Education Limited 2004 1.What are the three factors categories belonging to McCall’s factor model? 2.What factors included in each of the categories? 3.Some people claim that testability and verifiability are actually different names for the same factor 4.(a) Do you agree? 5.(b) If not, could you explain why?