Clock construction in fully asynchronous parallel systems and PRAM simulation

The authors discuss the question of simulating synchronous computations on asynchronous systems. They consider an asynchronous system with very weak, or altogether lacking any, atomicity assumptions. The first contribution of this paper is a novel clock for asynchronous systems. The clock is a basic tool for synchronization in the asynchronous environment. It is a very robust construction and can operate in a system with no atomicity assumptions, and in the presence of a dynamic scheduler. The behavior of the clock is obtained with overwhelming probability (1-2/sup - alpha n/, alpha >0). The authors show how to harness this clock to drive a PRAM simulation on an asynchronous system. The resulting simulation scheme is more efficient than existing ones, while actually relaxing the assumptions on the underlying asynchronous system.>