Reduction of ECAL data volume using lossless data compression techniques

We investigate the possibility of reducing the data size of the electromagnetic calorimeter (ECAL) of CMS detector at the Large Hadron Collider. The Selective Readout is applied to reduce the data size at a manageable level. Then various data compression methods are considered, and their performances estimated using the data from the full simulation of the ECAL system. A reduction of the average event size by a factor of two or larger is obtained in most cases.