The PHENIX DAQ system is managed by a control system responsible for the configuration and monitoring of the PHENIX detector hardware and readout software. At its core, the control system, called Runcontrol, is a process that manages the various components by way of a distributed architecture using CORBA. The control system, called Runcontrol, is a set of process that manages virtually all detector components through a distributed architecture base on CORBA. A key aspect of the distributed control system, the messaging system, is the ability to access critical detector state information, and deliver it to operators and applications of the control system. The goal of the system is to concentrate all output messages of the distributed processes, which would normally end up in log files or on a terminal, in a central place. The messages may originate from or be received by applications running on any of the multiple platforms which are in use including Linux, Windows, Solaris, and VxWorks. Listener applications allow the DAQ operators to get a comprehensive overview of all messages they are interested in, and also allows scripts or other programs to take automated action in response to certain messages. Messages are formatted to contain information about the source of the message, the message type, and its severity. Applications written to provide filtering of messages by the DAQ operators by type, severity and source will be presented. We will discuss the mechanism underlying this system, present examples of the use, and discuss performance and reliability issues.
E. desmond (BROOKHAVEN NATIONAL LAB)