FASTBUS SEGMENT EXTENSION AS A CRATE COUPLING TECHNIQUE

THE FASTBUS (MODULAR, HIGH-SPEED DATA ACQUISITION) SYSTEM SPECIFICATION FOR HIGH-ENERGY PHYSICS AND OTHER DATA SYSTEMSAPPLICATIONS HAS DETAILED A SEGMENT INTERCONNECT CONCEPT THAT ALLOWS A USER TO EXPAND A FASTBUS SYSTEM BEYOND THE 26 SLOT BASIC SEGMENT. THIS PROPOSAL DESCRIBES THE DEVELOPMENT OF A DIFFERENT TECHNIQUE, CALLED THE SEGMENT EXTENSION CONCEPT FOR FASTBUS CRATE COUPLING, THAT WILL ALLOW A FASTBUS SYSTEM TO BE EXPANDED BEYOND A SINGLE CRATE IN COST-EFFECTIVE WAY FOR THE SMALL-SYSTEM USER. THE PROPOSED EXPANSION TECHNIQUE WILL PROVIDE FOR THE EXTENSION OF A BASIC SEGMENT INTO A LARGER, BUT SINGLE, LOGICAL SEGMENT CONSISTING OF SEVERAL PHYSICAL SEGMENTS; SYSTEM EXPANSION IS ADDRESSED, WHILE THE COMPLEXITY OF THE COUPLINGSCHEME IS CONSIDERABLY REDUCED. THE FEASIBILITY DETERMINATION THAT MUST BE MADE DURING THE PHASE I RESEARCH PERIOD INCLUDES THE DETERMINATION OF THE MAXIMUM SIZE OF THEEXPANSION BY SEGMENT EXTENSION AND THE DEGRADATION IN FASTBUS CYCLE TIME BECAUSE OF EXPANDING THE SEGMENT TO A SINGLE LOGICAL SEGMENT.