REUSABLE AND ADAPTIVE SCHEDULERS FOR ADA REAL-TIME APPLICATIONS

THE NEED FOR USER DEFINED SCHEDULING IN THE USE OF THE ADA LANGUAGE HAS BEEN DOCUMENTED BY THE ADA9X PROCESS AND MANY OTHERS IN RECENT YEARS. THE RESEARCH OUTLINED BY THIS PROPOSAL IS ORIENTED TOWARD PROVIDING A REUSABLE APPROACH TO DEVELOPING SEMI-CUSTOM SCHEDULING ALGORITHMS FOR REAL-TIME ADA APPLICATIONS. THE SCHEDULING OF TASKS FOR HARD REAL-TIME APPLICATIONS HAS BEEN THE TOPIC OF CONSIDERABLE RESEARCH. MANY THEORIES HAVE BEEN DEVELOPED TO HELP SOLVE SCHEDULING PROBLEMS AND GUARANTEE THAT PROGRAMS WILL ACHIEVE THEIR TIMING DEADLINE REQUIREMENTS. THE ADA PROGRAMMING LANGUAGE PROVIDES A SIMPLE STANDARD TASK SCHEDULING CAPABILITY BUT IT DOES NOT PROVIDE SERVICES FOR MORE SOPHISTICATED AND FLEXIBLE SCHEDULING APPROACHES THAT CURRENTLY EXIST. THIS PROPOSAL DESCRIBES AN APPROACH TO BUILDING REUSABLE SCHEDULING COMPONENTS BASED ON AN INTERFACE TO THE ADA RUNTIME SCHEDULING PRIMITIVES. THE INTERFACE IS SUFFICIENTLY FLEXIBLE TO ALLOW A VERY WIDE VARIETY OF ALTERNATIVE SCHEDULING ALGORITHMS TO BE BUILT. BY BUILDING THE ALGORITHMS USING A STANDARD COMPONENT FORMAT AND A STANDARD SET OF SPECIFICATIONS, PERFORMANCE CHARACTERISTICS CAN BE GUARANTEED AND REUSE IS ENCOURAGED.