Data Acquisition System with Database at the SPring-8 Storage Ring

The SPring-8 storage ring control system has two kinds of access to the machine components, that is, an interactive operation and a periodic reading/monitoring operation. This paper describes the later. The machine status are periodically taken by processes on VME CPU(named the poller) and stored into shared memory. A process(collector client) running on the operator consoles cyclically collects the latest data set through its server process(named the collector server) running on the VME system. The collected data sets are sent to the on-line database by the collector client. Most of the machine status are updated every 5seconds. Many processes on the operator consoles can get current status of the machine from the on-line database without requiring direct access to the machine components. This data acquisition system provides good performance monitoring hundreds of devices without placing significant load on the VME CPU and network traffic.