ABSTRACT
The J-Machine is a distributed-memory, multiple instruction multiple data, concurrent computer. The grain size of a machine refers to the physical size and the amount of memory in one processing node. The J-Machine builds on previous work in the design of multiple processors and shared memory machines. The message-driven processor is an experiment in unifying shared-memory and multiple processors (MP) parallel computers. Shared-memory machines provide a uniform global name space that allows processing elements to access data regardless of their location. MP machines perform communication and synchronization via node-to-node messages. The dispatch mechanism is used directly to process messages requiring low latency. Messages become active either by arriving while the node is idle or executing at a lower priority, or by being at the head of a queue when the preceding message suspends execution. The message handler code may open additional segments by translating object IDs in the message into segment descriptors.
