The FASTBUS Segment Extension as a Crate Coupling Concept

The Segment Extension is a recent development in FASTBUS hardware that will require changes in the controlling software now being written for physics data acquisition systems. Applications involving the Segment Extension include the logical expansion of the front-end instrumentation crates holding electronics for the hundreds of particle detector channels planned for LEP experiments at CERN, the SLC experiments at SLAC, and CDF experiments at FERMILAB. This paper discusses the characteristics of the Segment Extension and the FASTBUS system-software requirements and hardware requirements imposed by the device.