COMP2002 Lecturecopyright DMU 2001 COMP2002 Quality Basics

COMP2002 LectureCopyright DMO2001 What is Quality? RQuality is.. ‘conformance to customer requirements’ R‘Quality is a catchall term R Quality refers to attributes of the processes and resources used to create and support the product.’

COMP2002 LectureCopyright DMO2001 Quality According to Crosby “Quality is conformance to requirements” RIf a product conforms to all requirements then it is a quality product. RLuxury is an aspect or attribute that is spelt out in the requirements. Phillip Crosby, ‘Quality Is Free’

COMP2002 LectureCopyright DMO2001 Quality According to the IEEE “Quality is the degree to which a system, component, or process meets customer or user needs or expectations” The IEEE standard

COMP2002 LectureCopyright DMO2001 Quality According to Weinberg R“Quality is value to some person” R“More quality for one person may mean less quality for another” R“Whose opinion of quality is to count when making decisions?” R“Quality is the absence of error” Gerald Weinberg, Quality Software Management, Vol 1

COMP2002 LectureCopyright DMO2001 Which Quality Approach? Crosby IEEE Weinberg To instill the basic discipline of meeting documented requirements To focus on the needs of clients To identify, specifically, which client’s needs we value

COMP2002 LectureCopyright DMO2001 Quality …... RSoftware quality is a multi-dimensional concept that is not easy to define in a simple way. RAchieving a high level of product or service quality is now the objective of most organisations

COMP2002 LectureCopyright DMO2001 Project Quality Project Requirements Resource Limitations Quality Objectives Functional Requirements "How Much?" List"How Well?" List"What?" List Taken from "Principles of Software Engineering Management" by Tom Gilb

COMP2002 LectureCopyright DMO2001 Quality Objectives Maintainability Testability Integrity Reliability Flexibility Reusability Portability Correctness Usability Efficiency

COMP2002 LectureCopyright DMO2001 Quality facts RQuality is relative. RQuality is almost always a political/emotional issue. RQuality is not the same as freedom from errors.

COMP2002 LectureCopyright DMO2001 Software QA Metrics R Identify key aspects of project - control, evaluation, improvement R Identify external events impacting project R Identify optimistic estimates R Calculate risks to project

COMP2002 LectureCopyright DMO2001 MetricDefinitionCharacteristics Addressed Size* Counts of physical source lines of codeSize, Progress, * Function points or feature pointsRe-use, Re-work Effort* No of staff hours/monthEffort, Cost, Re-work Resource, Allocations S/ware * Total no of errors open/closed Quality* No of errors open/closed since last reportQuality, Readiness for * Type of error (testing, action item,delivery, Improvement document comment)Trends, Re-work * Classification & priority * Product in which error was found Re-work* No of open/closed s/ware change orders * Total no of s/ware change orders Quality Assured, J McManus, Computer Bulletin Nov 2000

COMP2002 LectureCopyright DMO2001 Capability Maturity Model R Released 1991 R 400 companies certified to level 2 or above R Quantifies organisation’s ability to produce quality s/ware

COMP2002 LectureCopyright DMO2001 LevelKey Process Area 1. Initial S/ware development processes are notNone defined, the overall process is ad hoc & even chaotic. Success depends on individual effort 2. Repeatable Basic project management processes1. Requirements management are in place to track cost, schedule &2. S/ware project planning functionality. Methods are in place to3. Project tracking & over-sight repeat success achieved on similar4. S/ware subcontract manag. Programmes5. S/ware quality assurance 6. S/ware configuration management Quality Assured, J McManus, Computer Bulletin Nov 2000

COMP2002 LectureCopyright DMO2001 LevelKey Process Area 3. Defined 7. Organisation process focused The development process for both 8. Organisation process defined management & technical staff is 9. training programme standardised & documented. All 10. integrated s/ware managem projects use an approved tailored 11. s/ware product engineering version. 12. inter-group co-ordination 13. peer reviews 4. Managed The detailed measures of the s/ware14. Quantitative process manage process are collected, managed,15. S/ware quality manage. quantified, understood & controlled 5. Optimised The s/ware process continuously16. Defect prevention improves through quantified feedback17. Technology change manage from the process & testing of new ideas18. Process change manage. & technologies

COMP2002 LectureCopyright DMO2001 Quality Summary R Quality requires good technology R Quality requires good processes R Quality requires good people R Quality is everyone’s business Timothy Korson, OOP ‘97

COMP2002 LectureCopyright DMO2001 References RTimothy Korson, Ensuring Quality in Your O-O Projects, OOP ‘97, Munich RBarry McGibbon, Managing Your Move to Object Technology, SIGS 1995 RTom Gilb, Principles of Software Engineering Management, Dorset House 1987 RGerald Weinberg, Quality Software Management, Dorset House, 1991 RQuality Assured, J McManus, Computer Bulletin, Nov 2000