# Real-time mode-machines

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## Abstract

Modes are a natural abstract way of structuring the behaviour of complex systems. The different ways in which a system can operate are associated with different modes, and transitions link modes to form mode-machines. However, mode-machines need a precise semantics if they are to be used for specifying the behaviour of critical systems. This paper analyses the possible relationships between modes and states. A number of concurrent systems described using MASCOT are considered, and their mode-based behaviour is used to motivate the semantics of a new real-time mode-machine notation, RTMMs. It is argued that RTMMs should not behave like abstract state-machines. A list of concurrent transactions is associated with each RTMM mode, and a notation is given for specifying their timing properties. RTMM transactions need not terminate when the central mode-controller switches mode, thus capturing the asynchronous way in which large systems respond to mode changes. RTMMs are given a proof-theoretic semantics using many-sorted logic, extended with the RTL occurrence relation, Θ.

## Keywords

Execution Time Mode Change Concurrent System Concurrent Design Concurrent Transaction## Preview

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## References

- [ABR93]Audsley, N., Burns, A., Richardson, M., Tindall, K. and Wellings, A.J.: ‘Applying New Scheduling Theory to Static Priority Pre-emptive Scheduling',
*Softw. Eng. J.*, 1993, 8, (5), pp. 284–292Google Scholar - [Arm95]Armstrong, J.M.: ‘Aspects of Gradualistic Mode Transition Systems', Technical Report DCSC/TR/95/8, University of York, June 1995Google Scholar
- [Arn94]Arnold, A.: ‘Finite Transition Systems', Prentice-Hall International Series in Computer Science, 1994Google Scholar
- [Avn90]Avnur, A.: ‘Finite State Machines for Real-Time Software Engineering',
*Comp. and Cont. Eng. J.*, 1990, 1, (6), pp 273–278Google Scholar - [BJP87]Broy, M., Jackson, K., and Pennington, R.: ‘A Stream Function Definition of MASCOT', Technical Report, CO5255/FTR, Issue 1.1, System Designers Software Technology Centre, March 1987Google Scholar
- [Bur95]Burns, A.: ‘Preemptive Priority-Based Scheduling: An Appropriate Engineering Approach', pp. 225–248, in ‘Advances in Real-Time Systems'. Edited by S.H. Son, Prentice-Hall, 1995.Google Scholar
- [Cha95]Chapman, R.: 'static Timing Analysis and Program Proof', D.Phil. Thesis, Dept. of Computer Science, University of York, March 1995Google Scholar
- [Har87]Harel, D.: ‘Statecharts: A Visual Formalism for Complex Systems',
*Sci. of Comput. Prog.*, 1987, 8, pp. 231–274Google Scholar - [HMP92]Henzinger, T.A., Manna, Z., and Pnueli, A.: ‘Timed Transition Systems', Proc. ‘Real-Time: Theory in Practice', REX Workshop June 1991, Lect. Notes Comput. Sci., 600, (Springer-Verlag, 1992)Google Scholar
- [HoU79]Hopcroft, J.E., and Ullman, J.D.: ‘Introduction to Automata Theory, Languages, and Computation', Addison-Wesley Publishing Company, 1979Google Scholar
- [JaM86]Jahanian, F., and Mok, A.K: ‘Safety Analysis of Timing Properties in Real-Time Systems',
*IEEE Trans.*, 1986, SE-12, (9), pp. 890–904Google Scholar - [JaM94]Jahanian, F., and Mok, A.K.: ‘Modechart: A Specification Language for Real-Time Systems',
*IEEE Trans.*, 1994, SE-20, (12), pp. 933–947Google Scholar - [JIM87]Joint IECCA and MUF Committee on MASCOT (JIMCOM): ‘The Official Handbook of MASCOT', Version 3.1, Issue 1, Crown Copyright, June 1987Google Scholar
- [JLM88]Jahanian, F., Lee, R., and Mok, A.K.: 'semantics of Modechart in Real Time Logic', Proc. 21st Annual Hawaii Int. Conf. on System Science, 1988, pp. 479–489, 1988Google Scholar
- [JMS88]Jahanian, F., Mok, A.K., and Stuart, D.A.: ‘Formal Specification of Real-time Systems', Technical Report TR-88-25, Department of Computer Science, University of Texas at Austin, June 1988Google Scholar
- [Jos92]Joseph, M.: ‘Problems, Promises and Performance: Some Questions for Real-Time System Specification', Proc. of ‘Real-Time: Theory in Practice', REX Workshop June 1991, Lect. Notes in Comput. Sci., 600, (Springer-Verlag, 1992)Google Scholar
- [Man93]Manzano, M.: ‘Introduction to Many-Sorted Logic', in Meinke, K. and Tucker, J.V. (Ed.): ‘Many-Sorted Logic and its Applications', Wiley Professional Computing, 1993Google Scholar
- [MaP92]Manna, Z., and Pnueli, A.: ‘The Temporal Logic of Reactive and Concurrent Systems: Specification', Springer-Verlag, 1992Google Scholar
- [Pay93]Paynter, S.E.: ‘The Formalisation of Software Development Using MASCOT', Ph.D. Thesis, Mathematics Dept., University of Southampton, December 1993Google Scholar
- [Pay96]Paynter, S.E.: ‘Relating Mode-Machines and Concurrent Designs by a Process-Algebraic Foundation', To Appear, 1996.Google Scholar
- [Sim86]Simpson, H.R.: ‘The MASCOT Method',
*Softw. Eng. J.*, 1986, 1, (3), pp. 103–120Google Scholar - [Sim90]Simpson, H.R.: ‘Four-Slot Fully Asynchronous Communication Mechanism',
*IEE Proc. E.*, 1990, 137, (1), pp. 17–30Google Scholar - [Sim94a]Simpson, H.R.: ‘Methodological and Notational Conventions in DORIS Real-time Networks', IED Supporting Predictable Implementation of Requirements in Timing and Safety (SPIRITS) Deliverable, 1994Google Scholar
- [Sim94b]Simpson, H.R.: ‘Architecture for Computer Based Systems', IEEE Workshop on the Engineering of Computer Based Systems, Stockholm, 1994Google Scholar