Memory models of shared memory concurrent programs define the values a read of a shared memory location is allowed to see. Such memory models are typically weaker than the intuitive sequential consistency semantics to allow efficient execution. In this paper, we present WOMM (abbreviation for Weak Operational Memory Model) that formally unifies two sources of weak behavior in hardware memory mo...

Modern architectures provide weaker memory consistency guarantees than sequential consistency. These weaker guarantees allow programs to exhibit behaviours where the program statements appear to have executed out of program order. Fortunately, modern architectures provide memory barriers (fences) to enforce the program order between a pair of statements if needed. Due to the intricate semantics...

Optimistic replication of data is a widely used tool for mobile environments, but the behavior of concurrent conflicting updates caused by the relaxed consistency model is poorly understood. Through analytical modeling, we derive an exact bound for conflict rates for the common case of two replicas. The shape of the two-replica analytic curve matches well with simulation results at 50 replicas....

Sharing structured data today requires agreeing on a standard schema, then mapping and cleaning all of the data to achieve a single queriable mediated instance. However, for settings in which structured data is collaboratively authored by a large community, such as in the sciences, there is seldom consensus about how the data should be represented, what is correct, and which sources are authori...