UA1 data-acquisition system

The data-acquisition system of the UA1 experiment running at the CERN pp collider is described. The front-end electronics generates 1.6 Mbytes of raw data for each event. Parallel data-stream processors reduce the typical event data to 60000 bytes in a time of less than 10 ms. Data are read out by Remus CAMAC branches, formated data streams being read in parallel by buffer units with multi-event storage capability. For test and monitoring, the data flow can be accessed by local processors associated with each detector subsystem. Alternatively, the overall system can be partitioned off in a set of independent subsystems running their own data acquisition with or without a synchronous trigger. Online functions are assured by a number of multi-task and dedicated-task 16-bit and 32-bit computers. A variety of microprocessor-based systems with autonomous capabilities control the experimental apparatus.