Quality requirements of software products are often described in vague and broad terms. As a consequence it makes it difficult for software engineers to determine how quality influences their assignment and is it almost impossible for test engineers to evaluate the quality of the software product as no concrete and quantitative reference, of what quality in that context means, exists. The International Organization for Standardization (ISO) has defined a set of quality characteristics to enable the definition of software product quality in terms of functionality, reliability, usability, efficiency, maintainability and portability. These quality characteristics are described and defined in the ISO-9126 standard. In various annexes to this standard metrics are provided to actually measure the characteristics. Within Océ Technologies B.V., a Dutch developer and manufacturer of copying and printing equipment, the ISO-9126 standard has been used in the testing phase, to specify the software quality targets for the newest line of copier controller software. This copier controller software is a multi-site development project, which takes place in the Netherlands and France. Approximately 60 software engineers are involved in the project. This paper depicts, step-by-step, the actions taken to implement ISO-9126 in the project organisation and the results that were obtained. Described is how the most important quality characteristics (functionality, reliability and maintainability) were selected, by means of a questionnaire developed for the European SPACE-UFO project, to form a quality model. The next step on how to define and select the metrics to measure on the quality characteristics is described, including the determination of a baseline value for each metric. Finally the actual measurement during the test execution and the evaluation of the results obtained are discussed. During the evaluation of the results the relevance of the various metrics and the baseline values were analyzed and, if necessary, modified. An evaluation of the advantages and disadvantages of the approach taken concludes the paper.
Rob Hendriks has several years of experience within the area of software quality for embedded software systems, with a specialisation on software testing. The past years he has been working as a test co-ordinator and consultant in projects for consumer electronics and professional systems. On a regular basis he gives training in the area of software testing and has a specialisation in testing techniques. He is the co-author of the paper ‘Structured testing of embedded software’ published in Software Release Magazine in February 2000. Rob is co-founder of WEB, a study group for embedded software testing, which is a co-operation of companies, both development as service organisations, working in the area of technical automation.
Robert L.A.H. van Vonderen, MsC, has worked for Océ Technologies B.V. since his graduation from the Eindhoven University of Technology. He conducted a range of applied research studies in the area of embedded software, geographical information systems and printer controller software. In recent years he has worked as a project manager and project leader for the Océ Printing Systems division in the area of printer controllers and maintenance. He is currently responsible for the integration, testing and QA activities of the newest line of controller development within the Océ Document Printing Systems division.