Assertions about past and future: Communication in a high-performance distributed system Highways

Highways is a distributed-programming system, we are building, with high-performance as a major goal. The suite of send primitives implemented in Highways, called Global-Flush Primitives, have three no-table aspects. (1) Global-Flush Primitives permit one to make an assertion about messages sent in the past of sending m, in the future of sending m, about both or neither. (2) The past and the future of an event is defined using the relation "happened before." (3) A message can be sent to any subgroup of processes specified as a parameter.<
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