Hochstein, LorinBasili, Victor R.Computational scientists face many challenges when developing software that runs on large-scale parallel machines. However, their software development processes have not previously been studied in much detail by software engineering researchers. To better understand the nature of software development in this context, we examined five large-scale computational science software projects, known as the ASC-Alliance centers. We conducted interviews with project leads from all five of the centers to gain insight into the nature of the development processes of large-scale parallel code projects, and to identify issues in the current state-of-the-practice that reduce programmer productivity. The results of the interviews are summarized in this report.en-USTechnical Report