The EPICS Channel Archiver is used to store data exported by EPICS I/O Controllers (IOCs). The Channel Archiver acts as a Channel Access Client (CAC) and stores recorded data, acquired via periodic scan or monitored, into indexed binary files.MDSplus is a data management system used in several Nuclear Fusion experiments to handle experimental and configuration data. A data access Application Programming Interface (API) for local and remote data access is available for several languages, namely C, C++, Fortran, Java, Python, MATLAB and IDL, and a set of visualization tools is available for data browsing and display.The paper presents a new implementation of the EPICS Channel Archiver which uses MDSplus for data storage. In this way, it is possible to take advantage of the availability of the local and remote data access layers of MDSplus, widely used in the fusion community to handle large sets of data.A performance comparison between the original implementation and the new one is provided. In particular, the storage space requirements and the data access speed are considered.

The Ion Source experiment, called SPIDER, is the first experiment to be realized in the ITER Neutral Beam Test Facility under construction at Consorzio RFX, Padova, Italy. Its data acquisition system will provide the collection of around one thousand signals at a sampling rate ranging from a few Sample/s to 10 MSample/s and of diagnostics and inspection images produced at a frame frequency from 10 to 150 frame per second, for beam durations of up to one hour.As the final product of the Test Facility will be the ITER Heating Neutral Beam Injector, we decided follow the ITER CODAC guidelines. Therefore the EPICS system provided in the CODAC Core System has been assessed and adopted in plant control. In addition to EPICS, the MDSplus system will be adopted for the overall data management. MDSplus can handle a rich set of data types and offers support for both local and remote data access in a variety of languages, a feature not fully supported by EPICS. All experiment data in SPIDER will be maintained in a single MDSplus database containing both experiment configuration and acquired data. The seamless integration of EPICS and MDSplus in a single system requires the development of some new tools, namely: A Channel Archiver which provides storage into MDSplus pulse files of data produced by EPICS Input Output Controllers (IOC) and exported as Process Variables via Channel Access; a set of IOC records providing direct access from IOC into MDSPlus files; A Channel Access Server to export MDSplus data as EPICS Process Variables, making them directly accessible by IOCs.We expect that the integration of the two frameworks will result in a system that combines the best features from each system, i.e. the management of distributed Process Variables via channel access and the IOC concept for EPICS, the sophisticated data management and remote access for MDSplus.

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