Activity Report (2001 - 2003). Computing Research Center of KEK

An activity of Computing Research Center from 2001 to 2003 is reported. In the IT field, the network environment has been changed rapidly in these years, for example, from Internet to broad band network. Super SINET made a new research environment in the high energy physics, nuclear fusion, cosmophysics, biology, nanoscience and computing GRID by a very high speed network. With using the network, a large amount of experimental data from Belle group was analyzed among KEK, Nagoya, Tohoku and Tokyo University and Tokyo Institute of Technology. The report consists of eight chapters; the first chapter contains research and development of fourteen devices, the second chapter application of computer system, the third use of information system, the forth use of network system, the fifth security, the sixes user support, the seventh preparation of facility and the eighth materials and activity records. (S.Y.)