Single-step data transfer operations

A computer software product for data communications among a group of computing processes running on processors, which are interconnected by a communication medium, the product comprising a tangible, non-transitory computer-readable medium in which program instructions are stored, which instructions cause the processors to run a group of computing processes and to compose, for concurrent transmission by source processes in the group, messages comprising metadata indicating how data to be transmitted by the source processes are to be handled by destination processes in the group that are to receive the data and also comprising some of the messages the data to be transmitted by one or more of the source processes to one or more of the destination processes, while others of the messages comprise only the metadata, and

• to transmit the composed messages concurrently from the source processes to the destination processes in the group over the communication medium, and to process the data in the destination processes in response to the metadata comprised in the messages received by the destination processes.