CHORUS Distributed Operating System

The Cnonus technology has been designed for building o'new generations" of open, distributed, scalable Operating Systems. CHoRus has the following main characteristics: ¡ Ír comÍ[tnication-based technology, relying on a minimal Nucleus integrating distributed processing and communication at the lowest level, and providing generic services used by a set of subsystem servers to provide extended standard operating system interfaces (a UNIX interface has been developed, others such as OS/2 and object oriented systems are envisaged); @ Computing Systems, Vol. I 'No. 4 ' Fall 1988 305 . real-time services provided by the real-time Nucleus, and accessible by "system programmers" at the different system levels, . 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. CHonus-v3 is the current version of the Cuonus 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 Cnonus architecture and the facilities provided by the CHonus-v3 Nucleus. It describes the UNIX subsystem built vvith the Cnonus technology that provides: . binary compatibility with UNIX, . extended UNIX services supporting distributed applications (network IPC, distributed virtual memory), light-weight processes, and real-time facilities.