The J-Machine: A Fine-Gain Concurrent Computer

The J-Machine is a fine-grain concurrent computer that provides low-overhead primitive mechanisms for communication, synchronization, and translation. Communication mechanisms are provided that permit a node to send a message to any other node in the machine in < 2ps. On message arrival, a task is created and dispatched in < ljis. A translation mechanism supports a global virtual address space. These mechanisms efficiently support most proposed nodels of concurrei t computation. The hardware is an ensemble of up to 65,536 nodes each containing a 36-bit processor, 4K 36-bit words of memory, and a router. The nodes are connected by a highspeed 3-D mesh network. This design was chosen to make the most efficient use of available chip and board area.