Special purpose computing hardware for processing data from experiments

The life of a High Energy Physics experiment is divided into four stages; planning, setting up, data taking and analysis. The first and last of these stages are continually increasing the load and already overworked central computing facilities. This situation may be eased by moving some of the data reduction into the date taking stage, which is generally controlled by a minicomputer. Replacing the mini-computer by a faster and more powerful machine is a possible solution but more remarkable gains may be achieved by adding special computing hardware to which the minicomputer acts as a host. This paper outlines the design considerations and architecture of hardware intended for this application, and illustrates its usefulness in an experiment