CHIMERA II : a real-time UNIX-compatible multiprocessor operating system for sensor-based control applications

Abstract: "This paper describes the CHIMERA II multiprocessing operating system, which has been developed to provide the flexibility, performance, and UNIX-compatible interface needed for fast development and implementation of parallel real-time control code. The operating system is intended for sensor-based control applications such as robotics, process control, and manufacturing. The features of CHIMERA II include support for multiple general purpose CPUs; support for multiple special purpose processors and I/O devices; a UNIX-like environment, which supports most standard C system and library calls; standardized interrupt and exception handlers; and a user interface which serves as a terminal interface to the executing code. CHIMERA II also offers an attractive set of interprocessor communication features.The system-level express mail facility provides transparent access to a host file system and remote devices, and provides the basis for implementing user-level interprocessor communication. Application programmers have the choice of using shared memory, message passing, remote semaphores, or other special synchronization primitives for communicating between multiple processors. As an example of an actual implementation, we are currently using CHIMERA II to control a multi-sensor based robot system. The system runs on a Sun workstation host, with one or more Ironics M68020 processing boards, connected over a VME backplane. The system contains various special purpose processors, including a Mercury 3200 Floating Point Unit and an Androx Image Processor. The system also supports a variety of sensors and devices for real-time systems, which currently include a camera, force and tactile sensors, and a joystick."