This report summarizes the presentations and related discussions of the first international workshop on Theory and practice of open computational systems (TAPOCS) at the twelfth international workshop on Enabling technologies: Infrastructure for collaborative enterprises (WETICE). The balance between two topics of open computational systems in particular was in focus during the workshop discussions: theory and practice. As such, we introduced these topics by means of a presentation on Visions of open computational systems and concluded them by means of a presentation on an envisioned Roadmap of open computational systems.