Commit Quality in Five High Performance Computing Projects High Performance Computing (HPC) has a long history of software development but relatively little is known about the approaches this community uses to create and maintain software. To close this gap we study the practices of using version control tools in five HPC production projects. We also contrast these practices to practices used in three distinct non-HPC open source projects. We first obtain version history of the projects from SVN, Mercurial, and Git. We then clean and process the data and use published material to construct three measures of code commit quality: the fraction of unique commit comments, their size, and the number of files per commit. Our results indicate relatively high but declining commit quality, and relatively large commits in HPC projects. We expect this work to highlight the differences among different software engineering domains and may lead to ideas suggesting good practices of using software tools in these domains.