Data Monitoring System

A fraction of events are sampled on the online computer farm and sent to a PC server via Fast Ethernet for the real-time monitoring of data quality. The sampling rate is typically up to 20 Hz. On the PC server which is operated with Linux, the sampled data are placed on the shared memory and delivered to a set of monitoring programs under a control of a buffer manager, NOVA. Multiple monitoring programs including event displays run in parallel. The monitoring programs are developed in the off-line environment and can be plugged into the sampled data stream without affecting the execution of others.