Implementing train applications based on the distributed shared memory paradigm

A high speed trainset consists of a power car (or power cars) and trailer cars. Each car has its own processor which communicates via a network in the train. For dependability, most of data (objects) in memory are replicated on each processor. To design applications in the context of distributed systems, a simple and portable method consists in utilizing the Distributed Shared Memory (for short DSM) paradigm. On a group of Sun Workstations, an evaluation model has been implemented consisting in a set of hierarchical software layers to offer a DSM with two consistency criteria, namely sequential consistency and causal consistency. On top of this DSM, the application layer implements a typical train application software namely door management. In this train application software, focus was put on portability, dependability and safety issues.