A description is given of the Message-Driven Processor (MDP), an integrated multicomputer node. It incorporates a 36-bit integer processor, a memory management unit, a router for a 3D mesh network, a network interface, a 4K*36-bit word static RAM (SRAM), and an ECC dynamic RAM (DRAM) controller on a single 1.1 M-transistor VLSI chip. The MDP is not specialized for a single model of computation. Instead, it incorporates efficient primitive mechanisms for communication, synchronization, and naming. These mechanisms support most proposed parallel programming models. Each processing node of the MIT J-Machine consists of an MDP with 1 Mbit of DRAM.>

CST is a programming language based on Smalltalk-802 that supports concurrency using locks, asynchronous messages, and distributed objects. In this paper, we describe CST: the language and its implementation. Example programs and initial programming experience with CST are described. Our implementation of CST generates native code for the J-machine, a fine-grained concurrent computer. Some compiler optimizations developed in conjunction with that implementation are also described.

We propose a machine architecture for a high-performance processing node for a message-passing, MIMD concurrent computer. The principal mechanisms for attaining this goal are the direct execution and buffering of messages and a memory-based architecture that permits very fast context switches. Our architecture also includes a novel memory organization that permits both indexed and associative accesses and that incorporates an instruction buffer and message queue. Simulation results suggest that this architecture reduces message reception overhead by more than an order of magnitude.