Time-Efficient Read/Write Register in Crash-prone Asynchronous Message-Passing Systems

International audienceThe atomic register is one of the most basic and useful object of computing science, and its simple read-write semantics is appealing when programming distributed systems. Hence, its implementation on top of crash-prone asynchronous message-passing systems has received a lot of attention. It was shown that having a strict minority of processes that may crash is a necessary and sufficient requirement to build an atomic register on top of a crash-prone asynchronous message-passing system. This paper visits the notion of a fast implementation of an atomic register, and presents a new time-efficient asynchronous algorithm that reduces latency in many cases: a write operation always costs a round-trip delay, while a read operation costs a round-trip delay in favorable circumstances (intuitively, when it is not concurrent with a write). When designing this algorithm, the design spirit was to be as close as possible to the original algorithm proposed by Attiya, Bar-Noy, and Dolev