The CHORUS SystemThe Chorus project, at INRIA, designed and developed two operational versions of the CHORUS I Distributed Operating System, between 1980 and 1986 ([9,10]). CHORUS V2 has a UNIX ~ System V interface [I], and is currently used as a basis for supporting half a dozen of research distributed applications. A new version, CHORUS V3, has been developed by Chorus syst~mes [4], building on the experience of state-of-the art research systems such as CHORUS V2 [7], the V-System [3], Amoeba [5] and Mach [2], while taking into account constraints of the industrial environment.CHORUS V3 emphasizes portability, compatibility with standards and scalability [8], implying the ability to configure a system on a wide range of operational environments.
Autonomy in CHORUSCHORUS is an integrated distributed operating system: it is designed in order to allow its users to see a network of computers as a whole. Each node of a network runs the same kernel, which, similary to V or Amoeba, offers uniform and distribution transparent communication facilities. Autonomy in CHORUS is not considered at the computer or "machine" level, but at the individual resource level. Each resource, real or virtual, is managed by an independan~ server (e.g. a file server managing the files stored on a disk). In particular, each server is generally responsible for naming, access protection and sharing of the resource it manages.A number of similar autonomous servers can then cooperate, using the underlying transparent communication facilities, to provide an "integrated" service at a higher level.A user of the distributed system, i.e. a program running on a computer, is thus only dependent on:• the availability of the servers managing the resources it actually uses and,• a very small set of global services a CHORUS is a registered trademark of INRIA, licensed exclusively to Chorus syst~mes. 2UNIX is a registered trademark of AT&T.