CHIMERA II: A Real-Time UNIX-Compatible Multiprocessor Operating System for Sensor-Based Control Applications

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 high performance real-time multitasking kernel; user redefinable dynamic real-time schedulers; a UNIX-like environment, which supports most standard C system and library calls; standardized interrupt and exception handlers; and a user interface which serves to download, monitor, and debug code on any processor board, and 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. (kr) Sponsored in part by U.S. Army AMCOM and DARPA under contract DAAA-2189-C-0001, NASA under NAG5-1091.