A real-time executive generator

Abstract

Efficiency and responsiveness in operation and ease in programming is a conflict in designing a real-time executive. Manufacturer-provided general purpose executives are usually written with a high degree of generality so that they can be used over a wide range of different systems. This high versatility introduces considerable inefficiencies in executive operations. They normally require more core memory and processing time than a tightly-written, tailor-made program. On the other hand, the difficulties introduced by developing one's own executive, and the time and cost required to write and debug programs, are usually considerable. The purpose of this research was to develop a real-time executive generator, such as EXECGEN, to solve the difficulty in designing efficient executives. Various versions of the basic modules common to real-time executive programs were developed in sufficient detail. Also, the tables used to drive an executive to perform as a real-time executive were explicitly detailed. A users' specification language was developed. The generating phase was not specified in great detail. However, from the language and the presentation of the EXECGEN, a programmer could write an implementation of it. The effectiveness of EXECGEN was verified by generating an executive for a hypothetical airborne fire-control computer. The requirements for an executive were summarized in the form of the required users' specification. EXECGEN system logic was stimulated manually to produce a specific real-time executive. The "generated" executive was validated to assure the readiness for an intended mission by GPSS simulation for a typical job stream. The result of this research project was the development of an effective way to produce a real-time executive. The generated executive should be almost as efficient as one specifically coded for a given situation.