At the core of MISER is MISERnet, a real time
distributed database server engine. MISERnet servers distribute data to client
nodes, which can be other servers or workstations. MISERnet also provides the
master host communications with distributed and remote RTUs or controllers.
It also receives supervisory control commands from servers and workstations,
and then communicates these to RTUs and controllers. MISERnet collects, stores
and passes time stamped Change Of State (COS) data change events to the MISER historical database. MISERnet is an application level, inter-node communications facility that utilizes standard TCP/IP or DECnet OSI data transport protocols. MISERnet operates over standard Local Area Networks (Ethernet and FDDI) or Wide Area Networks without conflict with other network applications. MISERnet is required only to support MISER Software and is not involved in communications between non-MISER applications.
To provide high system availability of the MISERnet server functions, a redundant pair of hot backup server is usually provided. The on-line server continuously updates the backup server with current data, and automatically fails over to the backup server should the primary server fail. Periodic wellness messages are passed between the primary and backup servers; failure to communicate initiates fail over.
MISER supports a true client/server architecture. Xview performs display processing locally on the workstation, receiving only data from the MISER server engine. Xview keeps slide display files resident on the workstation hard disk drive, so call up times are typically less than one second. Current real time data is saved by Xview in a local copy of the MISER database, so slides come up with current data immediately. Once initialized, MISERnet updates the workstation database with data changes as they are processed by the server nodes. This client-server architecture, combined with the efficient COS data propagation methods used by MISERnet, maximizes overall network efficiency.
MISER does not have separate development and run time versions. MISER workstations are provided with all development tools, including both Xview and Xdraw. These tools support on-line operations and provide the properly privileged user with access to the slide, database and control logic development tools needed to build, maintain and enhance the system configuration. MISERnet automatically distributes system configuration changes to all workstations, eliminating the need to manually update these changes.