With the development of cluster computing, Distributed Shared Memory (DSM) systems have a new role to play by providing easiness of programming a shared space combined with the performance of high speed network.In this paper, we show that, by combining high performance network with low latency communication protocols and multithreading, DSM systems on top of clusters can be an efficient alternative programming model to message passing.We will present the DOSMOS system and experiments made on a Myrinet network based cluster. Raw performance of DOSMOS and results obtained with several kind of applications are also described.