The main goal of the HERA-B experiment which will start taking data in 1998 is to study CP violation in B decays. This article describes the concept and the planned implementation of a multi-processor system, called processor farm, as the last part of the data acquisition and trigger system of the HERA-B experiment. The third level trigger task and a full online event reconstruction will be performed on this processor farm, consisting of more then 100 powerful RISC processors which are based on commercial hardware boards. The controlling will be done by a real-time operating system which provides a software development environment, including FORTRAN and C compilers.