Final Report for Department of Energy MDSplus Development and Support Grant

MDSplus is a general-purpose data management system widely used across the magnetic fusion research community [Stillerman et al., 1997; Fredian et al., 2018]. Established in 1989 as a collaboration between MIT, CNR, and LANL, it has grown into the primary data infrastructure for major experiments including DIII-D and NSTX-U, and is in active use at more than 60 fusion research sites across six continents. Its architecture combines a hierarchical record store with a loosely typed expression evaluator, integrating data acquisition, metadata preservation, and analysis scheduling into a single framework. Since its inception on VMS, the software has been ported to all major modern operating systems (Linux, Windows, and macOS) while maintaining full backward compatibility: data written in 1989 remains readable by today's software. This is the final report for the five year period 2/1/2021 to 2/1/2026.