The ALEPH Event Builder

The Event Builder is a Fastbus module whose task is to collect data from different Readout Controllers in the ALEPH experiment. The task of `event building' is performed by a powerful MC68020 processor using the Motorola coprocessor concept to interface to Fastbus. The Fastbus coprocessor, built around a mixed sequencer and hardware machine architecture, enhances the instruction set of the MC68020 and thus makes Fastbus a native bus for the processor. From the user point of view, Fastbus calls are supported both by an Assembler and a Fortran compiler.