Event reconstruction of high energy electron-positron interactions, which will be observed in the ALEPH detector at LEP, represents a computational task which requires very large compute power, large program memory and only moderate input/output capacity. The intrinsic event-level parallelism of this task allows a solution based on an array of loosely coupled computers. A cost-effective solution is presented using commercial hardware, namely an Ethernet-based local area cluster of VAXstation processors. The parallel execution of the reconstruction program is achieved with minimal code modifications, by exploiting the fact that each processor runs a full operating system (VMS) and is able to do autonomous random access input/output. Results are shown of input/output performance and CPU utilization efficienc. These results were obtained on a prototype consisting of 6 VAXstation 3200 nodes and a micro VAX 3600 file server. The final system will start with 12 such nodes, giving a total capacity of 8 Mflops. © 1989.