Unisys Corporation

James W Douglas

David R Johnson

Joseph P Kerzman

Charles R Caldarale

James R McBreen

Merwin H Alferness

David C Johnson

Hans Christian Mikkelsen

Wayne D Ward

Mark D Aubel

Richard M Shelton

Donna J Plunkett

Francis A Stephens

A system and method for interprocess communication between concurrently executing, cooperating sequential processes in a digital computer system uses a shared memory queue as a mechanism for message passing and process synchronization. Data to be transferred from a sending process to a receiving process is stored in a queue entry which is visible in the virtual address space of the first process. The queue entry is added to a queue by the sending process directing the processor to execute an enqueue instruction. The receiving process removes the queue entry from the queue by directing the processor to execute a dequeue instruction. The receiving process then has direct access and visibility to the contents of the queue entry without having to copy the data into its virtual address space. Instead of sending data in a queue entry, a sending process may send an event indicator and no data. The receiving process may then wait on an empty queue until an event notification is received in a queue entry enqueued to the queue. Protection is provided by the system to prevent unauthorized access to the queue by other processes active in the system.

System architecture for improved message passing and process

Growing community of inventors

Forest Lake, MN, United States of America

James W Douglas