Abstract

INRIA Projet SOR (Systèmes d'objets répartis, or Distributed Object Systems) studies operating system support for information sharing in large-scale distributed systems. We seek system-level solutions, i.e. ones that are general, mutually orthogonal, scalable, application-independent and language-independent.

Our current focus is on the four following issues. First, the persistent distributed store (PDS) abstraction supports a simple API that programmers are already familiar with. Shared objects are mapped in memory and then accessed via pointers. Persistent objects are those that are accessible from some persistent root. In the past year we proposed Larchant, a PDS which incorporates a novel garbage collection algorithm. This year we concentrated on its implementation within PerDis, an Esprit LTR project. We are also working on the charactisation of applications that will use such a PDS.

Second, we provide an efficient and semantically-correct remote reference mechanism. Our Stub-Scion Pair (SSP) Chains are a fault-tolerant reference mechanism for identifying and accessing (possibly mobile and/or replicated) objects remotely. We now have a modular, robust, efficient implementation of the SSP chains in C++. This year, we concentrated on porting this system on Java, Objective-Caml, and Smalltalk. We also proposed a new protocol that could collect distributed cycles of garbage.

Third, in order to provide programmers with systems that really match their needs, we developped Core, a toolbox of components implementing multiple replication abstractions. Core allows application programmers to customize the internal policies of the underlying infrastructure. Our initial targets are fragmented object support, coherence management and storage systems.

Finally, we are developping a set of tools to support large scale cooperative work. These include a flexible distributed cache system, a cooperative bookmarks system, and support for mobile computing.

Précédent : Références Remonter : Projet SOR, Systèmes Objets Répartis