A distributed synchronization system for the TJ-II local area network

Synchronization mechanisms for the TJ-II local area network environment have been enhanced by the development of new capabilities. The mechanisms provide ''soft synchronization,'' that is notification of asynchronous events for situations in which some delay between the real event and message reception is not a critical point, e.g., start of pre-pulse phase, end of discharge, availability of the discharge file after a shot, trigger simulation for data acquisition tests and so on. The synchronization system is based on a distributed architecture where event servers are arranged in a tree structure. Event servers receive messages and then send them to other servers and client computers. The system is built on a two-layered configuration. The first one, devoted to network communication, is based on a de facto standard, Berkeley sockets, thus allowing for easy integration of multi-computer environments. The transport protocol is TCP in order to ensure the reliability needed. The second layer must provide support for local inter-process communication (LIPC) mechanisms. In this way, different processes can be synchronized within a single computer. Of course, this layer is system dependent