Transcript Document

SE513 Software Quality Assurance
Lecture02: Software Quality Factors
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004
• 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
2
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
3
“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
4
Software quality factors
Product operation factors
Product revision factors
Product transition factors
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004
5
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Correctness
Reliability
Efficiency
Integrity
Usability
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004
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• Maintainability
• Flexibility
• Testability
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004
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• Portability
• Reusability
• Interoperability
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004
8
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004
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Alternative factor models
No.
Software quality
factor
McCall’s classic
model
Evans and
Marciniak model
Deutsch and
Willis model
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Correctness
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2
3
4
5
6
7
Reliability
Efficiency
Integrity
Usability
Maintainability
Flexibility
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Testability
Portability
Reusability
Interoperability
Verifiability
Expandability
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Safety
Manageability
Survivability
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004
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Review questions
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?
Galin, SQA from Theory to Implementation
@Pearson Education Limited 2004