This report provides the detailed design of an operating system which can support the Vessel Traffic Services VTS application in a multicomputer, high reliability environment. Since computer hardware has not been selected, the design represents a generalized operating system which can be implemented on a wide variety of minicomputer systems which the Coast Guard may wish to select for the VTS ProcessingDisplay Subsystem. The discussion includes an overview of the Executive, a detailed description, as well as structure charts, Program Design Language specifications and a description of the system data structures used by the Executive. Basic considerations for the design and implementation of fault tolerant software, with specific application to VTS, are also presented. Constraints on hardware selection and assumptions that were made concerning manufacturer-provided development software, in regard to this VTSOS design, are cited.