System 75:The Oryx/Pecos Operating System
Gary R. Sager, J. A. Melber, Kelly Fong · AT&T Technical Journal · 1985
The System 75 Office Communication System is the first field application of the Oryx/Pecos operating system, a message-based system which supports real-time, distributed applications. Its interprocess communications mechanisms provide a structuring tool similar to monitors, capabilities, and abstract data types. This paper describes the principal concepts implemented in the operating system kernel, and presents the essential system processes. Support for application design techniques is discussed and related to proven software engineering principles, including information hiding and modularity. Specific examples are drawn from System 75 for call processing and maintenance.