Commonalities and differences between MDSplus and HDF5 data systems

MDSplus is a data acquisition system widely used in nuclear fusion experiments. It defines a file format for pulse files and provides a set of tools for data acquisition and management. The whole MDSplus package is used in several fusion experiments to set up and supervise the data acquisition process. Other experiments use only the data management layer of MDSplus to provide a common format for data exchange between plasma fusion laboratories.HDF5 is a file format and a data access library used by a larger community, mainly outside fusion. HDF5 is used, for example, in earth science research, defence applications and weather services. HDF5 allows managing large and complex data sets and provides a common data format among heterogeneous applications.Both MDSplus and HDF5 support a rich set of data types and a hierarchical data organization, as well as multi-language data access libraries. There are however several significant differences between the two system architectures, making each system better suited in different application contexts.The paper provides a brief overview of the data architectures of MDSplus and HDF5 and analyzes in detail the peculiar aspects of the two systems.