This paper describes a multiprocessor system designed and constructed by the authors. The hardware consists of eight MC68000 single board computers, a DEC VAX-11/750, and S/NET, a high speed message-oriented computer interconnect. The VAX processor operates under the UNIX operating system. The processors do not share memory; they are connected only through the S/NET. The system is structured as a connected network of service and server processors. The service processors form a pool which runs the application processes. The service processors control the physical and logical resources of the system. A dedicated single MC68000 processor provides access to and control over names, channels, and processes. A centralized server process running on the VAX provides file service. The paper reports on the performance of the system. It is claimed that the operating system software and the switch (S/NET) hardware provide interprocessor communication at high speed and low overhead, and that the system is well suited for a wide range of applications, communication-intensive to computation-intensive.