Object-oriented design for LHD data acquisition using client-server model

The LHD data acquisition system handles >600 MB data per shot. The fully distributed data processing and the object-oriented system design are the main principles of this system. Its wide flexibility has been realized by introducing the object-oriented method into the data processing, in which the object sharing and class libraries will provide the unified way of data handling for the network client-server programming. The object class libraries are described in C++, and the network object sharing is provided through the commercial software named HARNESS. As for the CAMAC setup, the Java script can use the C++ class libraries and thus establishes the relationship between the object-oriented database and the WWW server. In LHD experiments, the CAMAC system and the Windows NT operating system are applied for digitizing and acquiring data, respectively. For the purpose of the LHD data acquisition, the new CAMAC handling software on Windows NT have been developed to manipulate the SCSI-connected crate controllers. The CAMAC command lists and diagnostic data classes are shared between client and server computers. A lump of the diagnostic data can be treated as part of an object by the object-oriented programming.