The Spring Kerne: A New Paradigm for Hard Real-Time Operating Systems

Abstract

NEXT GENERATION, CRITICAL, HARD REAL-TIME SYSTEMS WILL REQUIRE GREATER FLEXIBILITY, DEPENDABILITY, AND PREDICTABILITY THAN IS COMMONLY FOUND IN TODAY''S SYSTEMS. THESE FUTURE SYSTEMS INCLUDE THE SPACE STATION, INTEGRATED VISION/ROBOTICS/AI SYSTEMS, COLLECTIONS OF HUMANS/ROBOTS COORDINATING TO ACHIEVE COMMON OBJECTIVES (USUALLY IN HAZARDOUS ENVIRONMENTS SUCH AS UNDER- SEA EXPLORATION OR CHEMICAL PLANTS), AND VARIOUS COMMAND AND CONTROL APPLI- CATIONS. THE SPRING KERNEL IS A RESEARCH ORIENTED KERNEL DESIGNED TO FORM THE BASIS OF A FLEXIBLE, HARD REAL-TIME OPERATING SYSTEM FOR SUCH APPLICA- TIONS. THE SPRING KERNEL IS BEING IMPLEMENTED IN STAGES ON A NETWORK OF (68020 AND 68030 BASED) MULTIPROCESSORS CALLED SPRINGNET. A PRELIMINARY VERSION OF THE KERNEL IS NOW OPERATIONAL. OUR RESEARCH APPROACH CHALLENGES SEVERAL BASIC ASSUMPTIONS UPON WHICH MOST CURRENT REAL-TIME OPERATING SYSTEMS ARE BUILT AND SUBSEQUENTLY ADVOCATES A `NEW PARADIGM'' BASED ON THE NOTION OF PREDICTABILITY AND ON A METHOD FOR ON-LINE DYNAMIC GUARANTEE OF DEADLINES. THE PURPOSE OF THIS PAPER IS TO PROVIDE AN OVERVIEW OF THE MAJOR IDEAS OF THIS NEW PARADIGM AND SHOW HOW THE KERNEL IMPLEMENTS THESE IDEAS. DETAILED DESCRIPTIONS OF BOTH THE KERNEL AND THE ALGORITHMS REFERRED TO IN THIS PAPER CAN BE FOUND IN THE REFERENCED MATERIAL.