Abstract.A commonly employed technique to control access to shared resources in concurrent programs consists of using critical sections. Unfortunately, it is well known that programs using several critical sections may suffer from deadlocks. In this paper we introduce a new approach for ensuring deadlock-freedom in a transparent manner from the programmer's point of view. Such an approach consists of obtaining a deadlock-free "version" of the original program by using some program transformations. We formally prove the correctness of those transformations and we analyze their applicability.

Abstract. In this paper we present a framework to formally describe and study the interconnection of distributed shared memory systems. In our models we minimize the dependencies between the original systems and the interconnection system (that is, they are decoupled) and consider systems implemented with invalidation and propagation. We first show that only fast (i.e. wait-free) memory models can be interconnected. We then show that causal and pRAM systems can be interconnected if they fulfill some restrictions, and for these cases, we present protocols to interconnect them. Finally, we present a protocol to interconnect cache systems.