Abstract
Since 1991, the California Institute of Technology has operated a massively parallel computer system on behalf of the concurrent supercomputing consortium (CSCC). The computer system is a distributed-memory multiple-instruction multiple-data (MIMD) system the nodes of which are connected in a two-dimensional mesh by mesh-routing chips. The system's file server, portability, acceptance tests, mode of operation, and national network connections are described. The hardware and software issues of the Delta system are discussed.