Basic Concepts for the Support of Distributed Systems: The Chorus Approach

The CHORUS technology has been designed for building new generations of open, distributed, scalable operating systems. CHORUS has the following main characteristics: g a communication-based architecture, relying on a minimal Nucleus which integrates distributed processing and communication at the lowest level, and which implements generic services used by a set of subsystem servers to extend standard operating system interfaces. A UNIX subsystem has been developed; other subsystems such as objectoriented systems are planned; g a real-time Nucleus providing real-time services which are accessible to system programmers; g a modular architecture providing scalability, and allowing, in particular, dynamic configuration of the system and its applications over a wide range of hardware and network configurations, including parallel and multiprocessor systems. CHORUS−V3 is the current version of the CHORUS Distributed Operating System, developed by Chorus systèmes. Earlier versions were studied and implemented within the Chorus research project at INRIA between 1979 and 1986. This paper presents the CHORUS architecture and the facilities provided by the CHORUS−V3 Nucleus. It also describes the UNIX subsystem built with the CHORUS technology that provides: g binary compatibility with UNIX; g extended UNIX services, supporting distributed applications by providing network IPC, distributed virtual memory, light-weight processes, and real-time facilities. hhhhhhhhhhhhhhhh This paper is a revised and updated version of an article published in ‘‘Computing Systems’’, The Journal of the Usenix Association, Volume 1, Number 4.  Chorus systèmes, 1991 − 1 − February 1, 1991 Chorus systèmes CHORUS Overview CS/TR-90-25.1