DS data server: sharing fusion-energy data and results

Recent years have see an upsurge in inter-laboratory collaboration within the fusion community. Also, increasingly powerful and inexpensive workstations, linked together by Local Area Networks and through the Internet, have become available for data analysis. It has therefore become essential to provide a mechanism for getting data from a central facility computer to application programs running on a diverse assortment of workstations and larger computers, both locally and at remote sites. The Data Server (DS) protocol defines a client/server communication standard to help satisfy this need. The protocol, a joint development project between PPPL and ORNL, was designed specifically to handle the type of experimental data (separate shot numbers, diagnostic specific) generated by the fusion energy community. It provides a flexible, machine-independent standard for network access to remotely stored data. Subroutines within the local data-access library, while retaining the same outward appearance, are modified to include client code for network data access. Through normal library calls, a user application transparently connects with an experiment-specific Server via TCP/IP over a Local Area Network or through the Internet. The server program presents its local data to the network client following protocol standards. By simple, well-defined request/reply transactions, the client (library routine) gets the information necessary for its normal operation. The network communication is entirely hidden from the user.