The purpose of the MAIN process is to start and stop FE, REC and MON child processes. It also provides the communication between the child processes and the Run Control program.
All interactions with electronics goes through and only through the FE process.
The REC process has a unique task of storing events on an I/O device. Recording can be done on disk files only, on the magnetic tape device only, or on both. As a tape device a DLT unit is used. Event recording is always done in an ``exchange'' mode allowing to read data later at any platform. User can setup the configuration parameters defining a name of tape drive, tape record size, maximum size of disk files, maximum size of tape files, tape capacity etc.
The purpose of the MON process is to provide events for the monitor daemon (MOND). It is not guaranteed that this process will take all events from buffers.
The monitor daemon program (MOND) works as a bridge between
the main dataflow
(FE 
REC) and user monitoring programs.
The monitoring programs can not affect the main dataflow by any means.
Remote monitoring programs can be started at any workstation with a TCP/IP connection to the target system. They verify the performance of the detector and the quality of the data during data acquisition. To visualize the results of the data analysis two programs were developed: one is based on the GTKPLOT package and another one on the ROOT system [6].
The run control program (CTRL) coordinates all activities in data taking and gives an operator the full control over entire DAQ system. This is a GTK+ [5] program which provides a graphical interface.
The online system also uses MySQL [7] database for storing time history of the data taking conditions, ambient data, and configuration parameters of hardware and software.