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Abstract

We investigate the nature of the scheduling problem as it arises in critical real-time systems, as well as the nature of its solutions. We establish that critical real-time systems must be designed as fault-tolerant distributed real-time systems. We argue that any provably correct solution to the scheduling problem must rest on on-line algorithms. Limitations of «solutions» currently used or proposed are examined. A design methodology is introduced, which serves the purpose of enforcing the timeliness proof obligation, such proofs being established under incomplete knowledge. Techniques that facilitate such proofs are pointed out and examples of solved problems are given.

Keywords

Schedule Problem Proof Obligation Earliest Deadline First Operational Scenario Relative Deadline 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. [1]
    M. Abadi, L. Lamport, «An old-fashioned recipe for real-time», DEC-SRC Research Report 91, Oct. 1992, 67 p.Google Scholar
  2. [2]
    H. Attiya, N.A. Lynch, «Time bounds for real-time process control in the presence of timing uncertainty», IEEE Real-Time Systems Symposium, Santa Monica (USA), 1989, 268–284.Google Scholar
  3. [3]
    S. Baruah et al., «On-line scheduling in the presence of overload», 32 nd Symposium on Foundations of Computer Science, 1991, 100–110.Google Scholar
  4. [4]
    P.A. Berstein, V. Hadzilacos, N. Goodman, «Concurrency control and recovery in database systems», (Addison-Wesley pub.), 1987, 370 p.Google Scholar
  5. [5]
    K.M. Chandy, L. Lamport, «Distributed snapshots: determining global states of distributed systems», ACM Transactions on Computer Systems, vol. 3, nℴ 1, Feb. 1985, 63–75.Google Scholar
  6. [6]
    X. Deng, C.H. Papadimitriou. «Competitive distributed decision-making», 12 th IFIP Congress (Elsevier North-Holland pub.), Madrid (Spain), 1992, vol. 1, 350–355.Google Scholar
  7. [7]
    K. Jeffay, D.F. Stanat, C.U. Martel, «On non-preemptive scheduling of periodic and sporadic tasks», IEEE Real-Time Systems Symposium, San Antonio (USA), 1991, 129–139.Google Scholar
  8. [8]
    M. Joseph, A, Goswami, «What's «real» about real-time systems ?», IEEE Real-Time Systems Symposium, Hunstville (USA), 1988, 78–85.Google Scholar
  9. [9]
    R.M. Karp, «On-line algorithms versus off-line algorithms: how much is it worth to know the future ?», 12th IFIP Congress (Elsevier North-Holland pub.), Madrid (Spain), 1992, vol. 1, 416–429.Google Scholar
  10. [10]
    H. Kopetz, G. Grünsteild, «TTP — a protocol for fault-tolerant real-time systems», IEEE Computer, Jan. 1994, 14–23.Google Scholar
  11. [11]
    H. Kopetz, P. Verissimo, «Real-time and dependability concepts», in «Distributed Systems» (Chapter 16), Sape Mullender Ed. (Addison-Wesley pub.), 1993.Google Scholar
  12. [12]
    L. Lamport, «Time, clocks and the ordering of events in a distributed system», Communications of the ACM, Vol. 21, 7, July 1978, 558–565.Google Scholar
  13. [13]
    J.C. Laprie (Ed), «Dependabilty: Basic conceps and terminology», vol. 5 of Dependable Computing and Fault-Tolerant Systems, Springer-Verlag, 1991.Google Scholar
  14. [14]
    C.L. Liu, J.W. Layland, «Scheduling algorithms for multiprogramming in a hard real-time environment», Journal of the ACM, Vol. 20, 1, Jan. 1973, 46–61.Google Scholar
  15. [15]
    G. Le Lann, «Distributed systems — Towards a formal approach», 6th IFIP Congress (North-Holland pub.), Toronto (Canada), 1977, 155–160.Google Scholar
  16. [16]
    G. Le Lann, «Certifiable critical complex computing systems», 13th IFIP Congress (Elsevier Science pub.)., Hamburg (Germany), Aug.–Sept. 1994.Google Scholar
  17. [17]
    G. Le Lann, N. Rivierre, «Real-time communications over broadcast networks: the CSMA-DCR and the DOD/CSMA-CD protocols», INRIA Research Report nℴ 1863, March 1993, 35 p.Google Scholar
  18. [18]
    J. Lundelius, N.A. Lynch, «An upper and lower bound for clock synchronization», Information and Control, vol. 62, 2–3, Aug./Sept. 1984, 190–204.Google Scholar
  19. [19]
    A.J. Martin, «Tomorrow's digital hardware will be asynchronous and verified», 12th IFIP Congress (Elsevier North-Holland pub.), Madrid (Spain), 1992, 684–695.Google Scholar
  20. [20]
    P. Muhlethaler, N. Rivierre, L. George, «Optimality and non-preemptive scheduling revisited», INRIA Research Report, to appear in 1994.Google Scholar
  21. [21]
    C.H. Papadimitriou, «The theory of concurrency control», Computer Science Press, Rockville (USA), 1986.Google Scholar
  22. [22]
    J. Rushby, «Formal methods and the certification of critical systems», SRI Technical Report, SRI-CSL-93-07, Nov. 1993, 308 p.Google Scholar
  23. [23]
    L. Sha, S.S. Sathaye, «A systematic approach to designing distributed real-time systems», IEEE Computer, Sept. 1993, 68–78.Google Scholar
  24. [24]
    K.W. Tindell, A. Burns, A.J. Wellings, «An extendible approach for analyzing fixed priority hard real-time tasks», Journal of Real-Time Systems, vol. 6, (Klüwer Academic pub.), 1994, 133–151.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1994

Authors and Affiliations

  • Gérard Le Lann
    • 1
  1. 1.Projet REFLECSINRIALe Chesnay CedexFrance

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