21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop 1 Quality for Components: Component and Component- Based Software Quality Issues Yusuf Altunel Istanbul Kültür University, Department of Computer Engineering Mehmet R. Tolun Çankaya University, Department of Computer Engineering

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop2 Outline Software components and component-based software systems have the capacity to enhance the productivity, reduce the time-to-market, and increase the confidence on the software. Build up software out of reusable components satisfying the quality requirements helps to meet the goals of software production. The problems of the component market and the market-oriented components prevent the wide application of component based software production. In this paper we investigate the quality related problems of CBD and the possible solutions.

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop3 Introduction Quality focus in component-based software engineering (CBSE) is the base layer methodology in the area must be based on Component market, is a priori condition to maximize the intra-organizational software reusability, cannot emerge without supplying high-quality products Building up software out of components Requires sufficient number of market components To make the selection out of choices Common belief: “Market components are not reliable” Prevents the emergence of mature market. Solution: Resolve quality problems of market components Third-party certification programs.

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop4 Definition : Product Quality “ ensuring the satisfaction of functional and non-functional characteristics, which will determine the level of user satisfaction and conforming expectations ” product characteristics Some will reduce the software quality, Some are neutral, some will reduce the quality. “ Software quality is defined as the level of a software system possessing the desired set of attributes [6], and lacking the undesired characteristics ” There is a need to define a methodology to specify software’s quality-related characteristics To define metrics to objectively measure product’s quality

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop5 Definitions A quality attribute a quality property representing a non-functional characteristics of a software system to assign a metric is a non-functional characteristic of a software system: Examples: functionality, reliability, usability, efficiency, maintainability, and portability. A quality model the set of characteristics and sub-characteristics to provide a basis in specifying the quality requirements of a software system

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop6 Quality Assurance (QA) Helps to localize the effects of changes on the product reducing the ripple effects. Component-based Quality Assurance: Increasing the modularity using components will increase the speed of incremental delivery help the developers to reduce time-to-market. Component reuse might cause integration difficulties, performance problems, incompatibility among products of different vendors. reliability and performance problems due to poor testing The main focus in CBD quality assurance to maximize the product quality adequately describe the quality characteristics increase the conformance to the standards

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop7 Importance of QA Trusting to the code constructed outside of the organization is a basic prerequisite to widespread use of commercial of-the-shelf (COTS) components Third-party component licensing To increase the trustworthiness of the components To discipline and enhance the overall quality of market components. confidence on the market components maintained showing the components satisfy functional and non-functional requirements. quality assurance activities help Increasing the externally developed software code reuse Appearing more suitable market conditions

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop8 Component Quality Assessment A metric for quality measurement a value that can be assigned to a quality attribute. To assess component quality define quality metrics with statistical evidence showing the correspondence between the quality and its metrics. code oriented measure is generally not feasible due to the lack of the source code for outsourced components. Quality metrics are used to evaluate the quality level of components before making the purchase or develop decisions.

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop9 CBSE Metrics Management metrics: cost, time to market, software engineering environment system resource utilization. Requirements metrics: requirements conformance, requirements stability. Quality oriented metrics: adaptability, complexity of interfaces and integration, integration test coverage, end-to-end test coverage, fault profiles, reliability, customer satisfaction

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop10 CBSE and Organization-wide Quality Improvement Strong interrelationship between CBSE and Organization-wide quality improvement set up tasks: Producing quality plan, Define and apply quality and productivity measures, Investigate the measures and measure results, Execute correction actions, Analyse the results. Some reasons of unsuccessful CBSE projects: Low process maturity, lacking the coordination and management, absence of well-tested, undocumented and ill-defined reuse oriented methods, models, and processes

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop11 Enhancement of CBSE Quality Component manufacturers: Establish organization-wide assessment standards. Discover the rules to define such standards Use the knowledge obtained from previous projects to adjust component production activities. Component consumers: Reuse might improve overall software quality Components are reusable software units Provide efficient reuse To reduce the quality assurance effort and integration problems

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop12 Issues in Implementing Systematic Reuse Managerial issues to promote and reward reuse, Economic issues to make reuse economical, Legal issues to protect the legal rights of reuse Technical issues to apply technical variables: design method, coding standards and practices, reuse library indexing methods.

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop13 Cost of Quality Costs of lacking the quality Internal failure costs the defects determined prior to delivery of shipment of the product Measured to analyse and improve the component development process External failure costs occur after the delivery or shipment of the product cover efforts to detect and correct problems Costs to achieve quality Appraisal costs: costs of measuring, evaluating, or auditing products assure conformance to quality standards and performance requirements. Measured for cost/benefit analysis To produce higher quality components and component-based software Prevention costs: Costs associated with activities designed to keep failure and appraisal costs to minimum

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop14 Conclusions The lack-of-the quality is a general problem of software development has a vital importance for CBSE: An obstacle preventing the wide application of the CBSE. CBSE provides a radical change in software development: construct the software systems out of quality components instead of developing every piece of code from scratch. wide application of software developed outside of the organization. confidence on the software developed outside of the organization the component producers must concentrate on quality issues Deal with extra costs and further activities Extra resource allocation increasing and assuring quality, identifying and mitigating the risks related with the quality quality planning and tracking activities

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop15 Conclusion-cont’d Radical change is required to Existing software development style Software development culture: continuous process improvement. Define formal processes Regular data collection to assess and improve the development Classical SW development methodologies not useful to reduce the number of failures lower than a certain level, Reason: every piece of code is developed from scratch Component defects Must be minimized in component-based software production. New SW development methodology To constructs SW out of qualified components Making the whole system More trustable, more efficient, easier to maintain better in user satisfaction.

21-22 May 2004IMPROQ 2004 / Impact of SW Processes on Quality Workshop 16 End of Presentation Questions and further discussions