Abstract
It has long been recognised that standard process algebra has difficulty dealing with actions of different priority, such as for instance an interrupt action of high priority. Various solutions have been proposed. We introduce a new approach, involving the addition of “priority guards” to Milner’s process calculus CCS. In our approach, priority is unstratified, meaning that actions are not assigned fixed levels, so that the same action can have different priority depending where it appears in a program. Unlike in other unstratified accounts of priority in CCS (such as that of Camilleri and Winskel), we treat inputs and outputs symmetrically. We introduce the new calculus, give examples, develop its theory (including bisimulation and equational laws), and compare it with existing approaches. We show that priority adds expressiveness to both CCS and the π-calculus.
Partially funded by EPSRC grant GR/K54663
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
J.C.M. Baeten, J. Bergstra, and J.-W. Klop. Syntax and defining equations for an interrupt mechanism in process algebra. Fundamenta Informaticae, 9:127–168, 1986.
J. Bergstra and J.-W. Klop. Process algebra for synchronous communication. Information and Computation, 60:109–137, 1984.
J. Camilleri and G. Winskel. CCS with priority choice. Information and Computation, 116(1):26–37, 1995.
R. Cleaveland and M.C.B. Hennessy. Priorities in process algebra. Information and Computation, 87(1/2):58–77, 1990.
R. Cleaveland, G. Lüttgen, and V. Natarajan. Priority in process algebra. In J.A. Bergstra, A. Ponse, and S.A. Smolka, editors, Handbook of Process Algebra. Elsevier, 2001.
C. Ene and T. Muntian. Expressiveness of point-to-point versus broadcast communications. In FCT’ 99, volume 1684 of Lecture Notes in Computer Science, pages 258–268. Springer-Verlag, 1999.
C.J. Fidge. A formal definition of priority in CSP. ACM Transactions on Programming Languages and Systems, 15(4):681–705, 1993.
H. Hansson and F. Orava. A process calculus with incomparable priorities. In Proceedings of the North American Process Algebra Workshop, pages 43–64, Stony Brook, New York, 1992. Springer-Verlag Workshops in Computer Science.
C.A.R. Hoare. Communicating Sequential Processes. Prentice-Hall, 1985.
A. Jeffrey. A typed, prioritized process algebra. Technical Report 13/93, Dept. of Computer Science, University of Sussex, 1993.
C.-T. Jensen. Prioritized and Independent Actions in Distributed Computer Systems. PhD thesis, Aarhus University, 1994.
R. Milner. Communication and Concurrency. Prentice-Hall, 1989.
R. Milner. Communicating and Mobile Systems: the π-calculus. Cambridge University Press, 1999.
R. Milner, J. Parrow, and D. Walker. A calculus of mobile processes. Information and Computation, 100:1–77, 1992.
V. Natarajan, L. Christoff, I. Christoff, and R. Cleaveland. Priorities and abstraction in process algebra. In P. S. Thiagarajan, editor, Foundations of Software Technology and Theoretical Computer Science, 14th Conference, volume 880 of Lecture Notes in Computer Science, pages 217–230. Springer-Verlag, 1994.
C. Palamidessi. Comparing the expressive power of the synchronous and the asynchronous π-calculus. In Proceedings of the 25th Annual Symposium on Principles of Programming Languages, POPL’ 97, pages 256–265. ACM, 1997.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2001 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Phillips, I. (2001). CCS with Priority Guards. In: Larsen, K.G., Nielsen, M. (eds) CONCUR 2001 — Concurrency Theory. CONCUR 2001. Lecture Notes in Computer Science, vol 2154. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-44685-0_21
Download citation
DOI: https://doi.org/10.1007/3-540-44685-0_21
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-42497-0
Online ISBN: 978-3-540-44685-9
eBook Packages: Springer Book Archive