A distributed, operating system based, blackboard architecture for real-time control

ABSTRACT

The design and implementation of a Distributed, Operating System based, Blackboard Architecture for Real-Time control (DOSBART) is described. DOSBART demonstrates the outstanding applicability of AI languages and blackboard techniques to the construction of versatile distributed real-time control frameworks. It provides a means to remotely and transparently execute operations on non-local objects, furnishing the ability to share data and blackboard structures transparently across a network of heterogeneous computers. It allows the simultaneous execution of all blackboard activities by utilizing the underlying operating system's multi-process functionality rather than its own scheduling mechanism. Architectural features are incorporated to deal with distributed real-time control issues such as interrupts, data dependencies, resource contention, activity control and I/O. Computation may occur in both process based and message based perspectives, and may be driven by a first order theorem prover that dynamically infers triggering events, by changes in demoned datums or by arbitrary predicates. The representational capabilities of the Common Lisp Object System (CLOS) were exploited to provide a rich set of base classes from which specific applications can be tailored. Lisp macro facilities support for multiple platforms.

REFERENCES

• Allworth: S. T. Allworth, Introduction to Real-Time Software Design, Springer-Verlag New York, Inc., Secaucus, NJ, 1988
• Bobrow: Daniel G. Bobrow , Linda G. DeMichiel , Richard P. Gabriel , Sonya E. Keene , Gregor Kiczales , David A. Moon, Common Lisp Object System specification, ACM SIGPLAN Notices, v.23 n.SI, p.1-142, September 1988 [doi>10.1145/885631.885632]
• Bond: Alan H. Bond , Les Gasser, Distributed Artificial Intelligence, Morgan Kaufmann Publishers Inc., San Francisco, CA, 1988
• Choobineh: Choobineh, F., Suri, R. (eds.), Flexible Manufacturing Systems, Industrial Engineering and Management Press, Norcross, GA, 1986, ISBN 0-89806- 078-8
• Coulouris: George F. Coulouris , Jean Dollimore, Distributed systems: concepts and design, Addison-Wesley Longman Publishing Co., Inc., Boston, MA, 1988
• Englemore: Englemore, R., Morgan, T. (eds.), Blackboard Systems, Addison-Wesley, Reading, MA, 1988, ISBN 0- 201-17431-6
• Fortier: Paul J. Fortier, Design of distributed operating systems: concepts and technology, Intertext Publications, Inc.,/McGraw-Hill, Inc., New York, NY, 1986
• Ginsberg: Ginsberg, M.L., "User's Guide to the MVL System", Stanford Tech. Memorandum 840-88-24, 1989
• Glass: Robert L. Glass, Real-Time Software, Prentice Hall PTR, Upper Saddle River, NJ, 1983
• Hayes: Barbara Hayes-Roth, A blackboard architecture for control, Artificial Intelligence, v.26 n.3, p.251-321, July 1985 [doi>10.1016/0004-3702(85)90063-3]
• Keene: S. E. Keene, A programmer's guide to object-oriented programming in Common LISP, Addison-Wesley Longman Publishing Co., Inc., Boston, MA, 1988
• Lampson: Lampson, B.W., Siegert, H.J. (eds.), Distributed Systems, Springer-Verlag, NY, NY, 1981, ISBN 0-387-12116-1
• Lauer: Hugh C. Lauer , Roger M. Needham, On the duality of operating system structures, ACM SIGOPS Operating Systems Review, v.13 n.2, p.3-19, April 1979 [doi>10.1145/850657.850658]
• Lesser: Lesser, V.R., Corkill, D.D., "The Distributed Vehicle Monitoring Testbed: a Tool for Investigating Distributed Problem Solving Networks", AI Magazine, Vol.4, No.3, 1983
• Maes: Pattie Maes , D. Nardi, Meta-Level Architectures and Reflection, Elsevier Science Inc., New York, NY, 1988
• Nii-1: Penny Nii, The blackboard model of problem solving, AI Magazine, v.7 n.2, p.38-53, Summer 1986
• Nii-2: Nii P., "CAGE and POLIGON: two Frameworks for Blackboard-Based Concurrent Problem Solving", Stanford Technical Report KSL-86-41, 1986 (also in {Englemore})
• Rashid: Rashid, R., F., "Threads of a New System", Unix Review, August 1986
• Reynolds: Reynolds, D., "Muse: A Toolkit for Embedded, Real-time AI", in {Englemore}

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
      I.2.8 Problem Solving, Control Methods, and Search
          Subjects: Plan execution, formation, and generation

Additional Classification:
  D. Software
  D.3 PROGRAMMING LANGUAGES
      D.3.2 Language Classifications

          Nouns: CLOS
  D.4 OPERATING SYSTEMS
      D.4.7 Organization and Design
          Subjects: Distributed systems

  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
      I.2.4 Knowledge Representation Formalisms and Methods
          Subjects: Representations (procedural and rule-based)

  J. Computer Applications
  J.7 COMPUTERS IN OTHER SYSTEMS
      Subjects: Real time; Command and control

General Terms:
Design, Languages