HND Computing Unit 8 Quality Management Prepared by S Hargrave Quality Activities HND Computing Unit 8 Quality Management Prepared by S Hargrave

Broader Aspects of Quality Safety Security Reliability Resilience Robustness Understandability Testability Adaptability Modularity Complexity Portability Usability Reusability Efficiency Learnability Quality management is not just concerned with ensuring that products are developed without faults and conform to specifications. It is also concerned with broader aspects of software quality. A critical part of quality planning is selecting critical quality attributes and planning how these can be achieved.

Quality Assurance Quality Planning Quality Control Quality managers are responsible for three kinds of activity: Quality Assurance - establishing organisational procedures and standards must to ensure high-quality products Quality Planning - selecting appropriate procedures and standards and tailoring them for a specific product Quality Control - ensuring that procedures and standards are followed by the development team QA is concerned with defining how an organisation aims to achieve quality. It involves defining or selecting standards that should be applied to the development process or product. These standards must be embedded in procedures or processes which are applied during development. These processes may be supported by tools that may have to be bought or specially developed during the QA process. Quality Control involves overseeing the development process to ensure that QA procedures and standards are being followed. This process has its own set of procedures and reports that must be defined and applied during the development process. As far as possible, these procedures should be straight forward and easily understood by the developers.

International Standards ISO 9000 ISO 9000-3 BS5750 ISO 9001 An international standard that can be used in the development f a quality system in all industries from manufacturing through to service industries. ISO 9001 is the most general of these standards and applies to organisations concerned with the quality process in organisations which design, develop and maintain products. A supporting document (ISO 9000 - 3) interprets ISO 9000 for software development. Each country has its own national standards which instantiate the ISO 9000 standards for that country. In the UK, the appropriate standard is BS 5750. The standards are expressed in a rather formal and stilted way. ISO 9001 is a generic model of a quality process. It describes various aspects of that process and defines which standards and and procedures should exist within an organisation. IT is not industry specific and so it is not defined in detail. Within any organisation a set of appropriate quality processes should be defined and documented in an organisational quality manual.

Areas covered by ISO 9001 Management Responsibility Control - non-conformance Handling, storing, packaging and delivery Purchased products Process control Inspection and test equipment Contract Review Document control Internal quality audits Servicing Quality System Design control Purchasing Product identification and traceability Inspection and testing Inspection and test status Corrective action Quality records Training Statistical techniques The list above show the areas covered by ISO 9001. Ince (1994) gives a detailed account of how the standard can be used to develop software quality management processes. Quality assurance procedures should be documented in a quality manual which defines the quality process. Customers are increasingly looking for ISO 9000 certification in a supplier as an indicator as to how seriously that supplier takes quality. ISO 9000 and Software Quality Assurance - Ince 1994

ISO 9000 Quality models Organisation Quality Manual Organisational instantiated as Organisation Quality Manual documents Organisational quality process is used to develop instantiated as Project quality management Project 1 quality plan Project 2 quality plan Project 3 quality plan The diagram shows the relationship between ISO 9000, the quality manual and individual quality plans. Quality planning should begin at an early stage in the software process and a plan should set out the desired product qualities. It should define how these are to be assessed. Without such a definition, different developers may work in an opposing way so that different product attributes are optimised. The plan should clearly set out which quality attributes are most significant for for the product being developed. The plan should also define the quality assessment process. This should be a standard way of assessing whether some quality, such as maintainability, is present in the product. The quality plan should select organisational standards that are appropriate to the particular product and development process. New standards may have to be defined if the project uses new methods and tools. The plan need not include details of particular standards. IT may simply reference these in the quality manual..

Process-based quality Define Process Develop Product Assess product quality No Quality OK? Yes Improve process Standardise Process An underlying assumption of quality management is that the quality of the development process directly affects the quality of delivered products. This is derived from manufacturing systems where product quality is intimately related to the production process. This approach to quality assurance is illustrated in the diagram. Process quality is particularly important in software development.The reason is that it is difficult to measure software attributes, such as maintainability, without using the software for a long period. Quality improvement focuses on identifying good quality products, examining the processes used to develop these products then generalising these processes so that they may be applied across a range of products. The relationship between software process and software product quality is complex. Changing the process does not necessarily lead to improved product quality. There is a clear link between process and product quality in manufacturing because the process is relatively easy to standardise and monitor.

Software quality process Define process standards Monitor the development process Reporting software process Quality managers must ensure the quality of the software process that is used. This involves: defining process standards such as how reviews should be conducted, when reviews should beheld and so on; monitoring the development process to ensure that the standards are being followed; reporting the software process to project management and t the buyer of the software. A danger of process-based quality assurance is that the prescribed process may be inappropriate for the type of software being developed. For example, process quality standards may specify that specification must be complete and approved before implementation can begin. However, some systems may require prototyping which involves program implementation. The quality team may suggest that this prototyping should not be carried out because its quality cannot be monitored.

Quality Reviews Review Type Design or program inspections Progress Reviews Quality Reviews Principal Purpose Detection of errors and standards checking Provide Management Information Technical analysis of components/documentation Reviews are the principal method of validating the quality of a process or product. They involve a group of people examining part or all of a process, system or its associated documentation to discover potential problems. The conclusions of the review are formally recorded and passed to the person responsible for correcting discovered problems. Program reviews are to detect detailed errors in the design or code and to check whether standards have been followed. This review should be driven by a checklist of possible errors. Progress reviews are part of the management process and provide management information about the overall progress of the project. This is both a process and a product review and is concerned with costs, plans and schedules. Quality reviews are to carry out a technical analysis of product components or documentation to find faults or mismatches between the specification and the design, code or documentation. It may also be concerned with broader quality issues such as adherence to standards and other quality attributes.

Software Standards Provide an encapsulation of best practice Provide a framework Assist in continuity (IEEE 1994) One of the most important roles of the quality assurance team is the development of product and process standards. Product standards define characteristics that all product components should show. Process standards define how the software process should be conducted. An example of a product standard is a review form which defines the information to be collected during a review. And example of a process standard is a procedural definition of how design reviews should be organised. Standards are important for a number of reasons: They provide an encapsulation of best, or at least most appropriate, practice. This knowledge is often only acquired after a great deal of trial and error. Building it into a standard avoids the repetition of past mistakes. The standard should capture some wisdom which is of value to the organisation. They provide a framework around which the QA process may be implemented. Given that standards encapsulate best practice, quality assurance becomes the activity of ensuring that standards have been properly followed. They assist in continuity where work carried out by one person is taken up and continued by another. Standards ensure that all engineers within an organisation adopt the same practices. Consequently, learning effort when starting new work is reduced. National and international standards have been developed covering software engineering (IEEE 1994)

Product and Process Standards Product Standards Design review form Document naming standards Procedure header format Ada programming style std Project plan format Change request form Process Standards Design review conduct Submission of documents to CM Version release process Project plan approval process Change control process Test recording process QA teams who are developing standards should normally base them on national and international standards. Developed standards should be drawn up in a handbook which defines those standards which are appropriate for their organisation. A sample of these are shown in the table.

Documentation Standards Documentation process standards Document standards Document interchange standards Document standards are particularly important, especially in a software project, since they are the only tangible way of representing the software and software process. There are three types of document process standards: Documentation process standards - these define the process which should be followed for document production. Document standards - these are standards which govern the documents themselves. Document interchange standards - it is increasingly important to exchange copies of documents via electronic mail and to store documents in databases. Interchange standards ensure that all electronic copies of documents are compatible.

Document production process Drafting, checking, revising and re-drafting is an iterative process. It should be continued until a document of acceptable quality is produced . The acceptable quality level will depend on the document type and the potential readers of the document. Document standards apply to all documents produced in the course of a projects development. They should have a consistent appearance and documents of the same class should have a consistent structure. Document process quality assurance standards must be flexible and must be able to cope with all types of document. For working papers or memos, there is no need for explicit quality checking. However where documents are formal documents used for further development or are released to customers, a formal quality process should be adopted. The diagram illustrates just one possible process.