Towards an Optimistic Management of Concurrency: A Probabilistic Study of the Pilgrim Protocol

  • Eric Garcia
  • Hervé Guyennet
  • Julien Henriet
  • Jean-Christophe Lapayre
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3865)


In CSCW applications, users modify shared objects in real-time. Thus, concurrency management protocols are required in order to maintain consistency. Such protocols can be classified as optimistic or pessimistic. Our Pilgrim protocol is pessimistic since it is based on ownership. Our new version of this protocol is optimistic and designed to minimize the delay before writing. This paper presents this new version based on atomization and multi-versioning and compares it to the former one through a probabilistic study. Finally, this study allows us to highlight the parameters that make it possible to choose between the two protocols studied.


Optimistic Protocol Probabilistic Study Shared Object Finite State Automaton Computer Support Cooperative Work 
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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  1. 1.
    Ba, T., Garcia, E., Henriet, J., Lapayre, J.-C.: The Optimistic Pilgrim: Proof and Validation. Technical Report RT2004-02, LIFC (2004),
  2. 2.
    Birman, K.P.: The Process Group Approach to Reliable Distributed Computing. Communications of the ACM 36(12), 37–53 (1993)CrossRefGoogle Scholar
  3. 3.
    Birman, K.P., Hayden, M., Hickey, J., Kreitz, C., Van Renesse, R., Rodeh, O., Constable, B., Vogels, W.: The Horus and Ensemble Projects: Accomplishments and Limitations. In: Proceedings of DARPA Information Survivability Conference and Exposition (DISCEX 2000), Hilton Head, SC, vol. 1, pp. 149–161 (2000)Google Scholar
  4. 4.
    Broom, B.: Aspects of Interactive Program Display. Doctoral dissertation. Department of Computer Science, university of Queensland, Australia (1987)Google Scholar
  5. 5.
    Chevassut, O., Berket, K., Agarwal, D.A.: A Practical Approach to the InterGroup Protocols. Future Generation Computer Systems 18(5), 709–719 (2002)CrossRefGoogle Scholar
  6. 6.
    Dommel, H.P., Garcia-Lunes, J.J.: Floor control for multimedia conferencing and collaboration. Multimedia Systems 5, 23–38 (1997)CrossRefGoogle Scholar
  7. 7.
    Ellis, C., Wainer, C.: A conceptuel model of Groupware. In: Proceedings of CSCW 1994, Chapel Hill, NC, USA, pp. 79–88. ACM Press, New York (1994)Google Scholar
  8. 8.
    Garcia, E., Lapayre, J.-C., David, G.: Pilgrim Performance over a New CAliF Communication Layer. In: IEEE Proceedings of the ICPADS 2000, Iwate, Japan, pp. 203–210 (2000)Google Scholar
  9. 9.
    Greenberg, S., Marwood, D.: Real Time Groupware as a Distributed System: Concurrency Control and its effect on the Interface. In: Proceedings of CSCW 1994, Chapel Hill, NC, USA, pp. 207–217. ACM Press, New York (1994)Google Scholar
  10. 10.
    Kaashoek, M.F., Tanenbaum, A.S.: An Evaluation of the Amoeba Group Communication System. In: International Conference on Distributed Computing Systems, Hong Kong, pp. 436–448 (1996)Google Scholar
  11. 11.
    Kramer, S., Amir, Y., Dolev, D., Malki, D.: Transis: A Communication Subsystem for High Availability. In: FTCS-22: 22nd International Symposium on Fault Tolerant Computing, Boston, USA, pp. 76–84. IEEE Computer Society Press, Los Alamitos (1992)Google Scholar
  12. 12.
    Lamport, L.: Time, clocks and the ordering of events in a distributed system. Communications of the ACM 21(7), 558–565 (1978)CrossRefzbMATHGoogle Scholar
  13. 13.
    Sun, C., Chen, D.: A Multi-version Approach to Conflict Resolution in Distributed Groupware Systems. In: Proceedings of the ICDCS 2000 International Conference, Tapei, China, pp. 316–325 (2000)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Eric Garcia
    • 1
  • Hervé Guyennet
    • 1
  • Julien Henriet
    • 1
  • Jean-Christophe Lapayre
    • 1
  1. 1.Laboratoire Informatique de l’Université de Franche-ComtéFRE CNRSFrance

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