Mapping modern software process engineering techniques onto an HEP development environment

One of the most challenging issues faced in HEP in recent years is the question of how to capitalise on software development and maintenance experience in a continuous manner. To capitalise means in our context to evaluate and apply new process technologies as they arise, and to further evolve technologies already widely in use. It also implies the definition and adoption of standards. The CMS off- line software improvement effort aims at continual software quality improvement, and continual improvement in the efficiency of the working environment with the goal to facilitate doing great new physics. To achieve this, we followed a process improvement program based on ISO-15504, and Rational Unified Process. This experiment in software process improvement in HEP has been progressing now for a period of 3 years. Taking previous experience from ATLAS and SPIDER into account, we used a soft approach of continuous change within the limits of current culture to create of de facto software process standards within the CMS off line community as the only viable route to a successful software process improvement program in HEP. We will present the CMS approach to software process improvement in this process R&D, describe lessons learned, and mistakes made. We will demonstrate the benefits gained, and the current status of the software processes established in CMS off-line software.