corba technology in reengineering the FTU data acquisition system

In its early stages, Frascati tokamak upgrade DAS was essentially devoted to acquiring data from experiments in CAMAC standard, using a software system (code and database) entirely written by domestic professionals. In 15 years of life DAS has been growing in size and complexity, still preserving its original structure; at the same time new standards were introduced (VME, PCI) to take into account users’ ever increasing demands for amount of data and acquisition frequency with which the existing code couldnʹt cope. Moreover, machines were getting old and the maintenance became troublesome. Finally, the data archive porting to Unix has definitely shown that the DAS system was ageing and a thorough redesign was needed. The system we are planning to introduce is founded on a standard corba bus: (i) to integrate heterogeneous platforms and define a standard layer for interactions between the different acquisition units; (ii)to grant, with open source tools (MySql) and interfaces (Html and Java), unified access to hardware and software configuration data. So, a dedicated PC server, connected via a suitable PCI serial highway driver card, will perform the CAMAC access for all the clients interacting through the corba layer. Up to now we have successfully tested CAMAC access, and we designed an acquisition unit, which will be the building block of the new system. The next step will be migrating to Alpha/VMS the software related to CAMAC data acquisition, which has been so far the cornerstone of the whole DAS; it will be completely redesigned to fit the ‘acquisition unit’ paradigm we have defined. Finally we will have a fully distributed data acquisition system with VME (at present six such units have been operating since 1999) and PCI stations, an Alpha/VMS client of the CAMAC/PC server and any possible platform interacting through a corba bus for getting data configuration, synchronisation and data archiving.