No. 125 (00267)

Family name : Itoh
Given name : Ryosuke
Affiliation : IPNS, KEK
Abbreviation : KEK
E-mail address : ryosuke.itoh@kek.jp
Title : Realtime Event Reconstruction Farm for Belle Experiment
Authors : Ryosuke Itoh
Abstract : 
A sizeable increase in the machine luminosity of KEKB accelerator is
expected in coming years. This results in a massive increase in the data
storage resource for the Belle experiment and it is desired to reduce
the data flow as much as possible before writing the data to the storage
device. 

For this purpose, a realtime event reconstruction farm has been built.
The farm consists of a number of (>30) PC servers and the event flow
from the DAQ system is directly distributed to them to be processed in
parallel. A full event reconstruction is done on each server so that a
sophisticated event selection can be performed to reduce the data flow. 

The architecture of the farm is described at the conference. In
particluar, the software framework for the parallel event processing is
discussed in detail. The performance of the system in the beam runs is
reported also.