Portable data flow in Unix

We describe the dataflow of a nuclear physics data acquisition system. The system features a high speed active routing subsystem which allows an arbitrary number of data producers to contribute data to the system. Data are then routed to an arbitrary number of data consumers. Low overhead route-by-reference mechanisms are used to allow high rate operations. The system has been ported to a variety of [UNIX.sup.tm] systems. Timings are given for the routing component of the system on several systems. Finally, we give an example of a set of programs which can be added to the system to produce a complete data acquisition system.