This is very preliminary description of the PHOBOS Data Acquisition Program.
The phatdaq is the main Phat program it comprises:
The UDP communication is secured by simple handshaking when recipient confirms each message. Using UDP protocol make it possible to significantly reduce overhead (3 times in comparison with TCP), avoid data splitting between packets and to organize well defined handshake.
The handshaking between VME Read Out Controller and phatdaq takes less then 2 ms. That means that using rudimentary event building scheme when all ROCs receive confirmation from phatdaq that the event was accepted, we can achieve 500 events/sec or 5 Mbytes/sec.
Files:
rmain.cxx - phatdaq source
daq.h classes and structures
daqmessages.h - definition of all messages
runcontrol_init.C - ROOT macro for initialization
runcontrol_command.C
ROOT macro for control of the phatdaq
runcontrol_exit.C - ROOT
macro for graceful exit of phatdaq and all ROCs
TODO
:
Andrei Sukhanov 02/04/00 01:38:04 PM