Parallelism at CERN: real-time and off-line applications in the GP-MIMD2 project

A wide range of General Purpose High-Energy Physics applications, ranging from Monte carlo simulation to data acquisition, from interactive data analysis to on-line filtering, have been ported, or developed, and run in parallel on IBM SP-2 and Meiko CS-2 CERN large multi-processor machines. PRIT project GP-MIMD2 has been a catalyst for the interest in parallel computing at CERN. The project provided the 128 processors Meiko CS-2 system that is now succesfully integrated in the CERN computing environment. RN experiment NA48 was involved in the GP-MIMD2 project since the beginning. NA48 physicists run, as part of their day-to-day work, simulation and analysis programs parallelized using the Message Passing Interface MPI. The CS-2 is also a vital component of the experiment Data Acquisition System and will be used to calibrate in real-time the 13 000 channels liquid krypton calorimeter.