This Article 
   
 Share 
   
 Bibliographic References 
   
 Add to: 
 
Digg
Furl
Spurl
Blink
Simpy
Google
Del.icio.us
Y!MyWeb
 
 Search 
   
Tolerating Sensor Timing Faults in Highly Responsive Hard Real-Time Systems
February 1995 (vol. 44 no. 2)
pp. 181-191

Abstract—Real-time systems that have to respond to environmental state changes within a very short latency period often use event-triggered task activation. If the system has to function correctly in the presence of sensor faults, event-triggered task activation is not reliable. Faulty sensors may cause task activations to occur too early, too late, or task activations are omitted entirely. In particular, early task activations can overload the system. Time-triggered task activation is reliable, but by defining a competitiveness ratio it is shown that the processor utilization for highly responsive tasks is unacceptably low. To overcome the problems of event-triggered task activation while preserving its good performance the task-splitting model is introduced. The task-splitting model integrates fault tolerance into the analysis and construction of hard real-time systems by using a combination of event-triggered and time-triggered task activation. Based on a general task model, it is independent of any particular scheduling algorithm. The result of this work has influenced the design of a new operating system which will be applied in a robust automotive engine controller of the next generation.

Index Terms—Sensor timing faults, fault tolerance, hard real-time systems, event-triggered task activation, competitiveness of task activation.

[1] M. Chen and K. Lin, “Dynamic Priority Ceiling: A Concurrency Control Protocol for Real-Time Systems,” J. Real-Time Systems, vol. 2, no. 1, pp. 325-346, 1990.
[2] Y.-K. Chin and F. E. Coats,“Engine dynamics: Time-based versus crank angle based,”inSAE Int. Congress and Exposition, Feb. 1986, pp. 15–35.
[3] F. Cristian, H. Aghili, R. Strong, and D. Dolev,“Atomic broadcast: From simple message diffusion to Byzantine agreement,”inProc. 15th Symp. Fault-Tolerant Computing, June 1985, pp. 200–206.
[4] R. Gerber and S. Hong,“Compiler support for real-time programs,”inProc. 14th IEEE Real-Time Syst. Symp., Dec. 1993, pp. 232–242.
[5] J. Hong, X. Tan, and D. Tosley,“A performance analysis of minimum laxity and earliest deadline scheduling in a real-time system,”IEEE Trans. Comput., vol. 38, no. 12, pp. 1736–1744, Dec. 1989.
[6] M. Joseph and P. Pandya,“Finding response times in a real-time system,”The Comput. J., vol. 29, no. 5, pp. 390–395, 1986.
[7] H. Kopetz and K. Ki,“Temporal uncertainties in interaction among real-time objects,”inProc. 9th Symp. Reliable Distributed Syst., Oct. 1990, pp. 165–174.
[8] H. Kopetz,“Event-triggered versus time-triggered real-time systems,”Technical Report 8/91, Institut für Technische Informatik TU Vienna, Austria, Mar. 1991.
[9] J. Lehoczky, L. Sha, and Y. Ding,“The rate monotonic scheduling algorithm: Exact characterisation and average case behavior,”inProc. IEEE Real-Time Syst. Symp., 1989, pp. 166–171.
[10] J. Lehoczky, L. Sha, and J. Strosnider,“Enhancing aperiodic responsiveness in a hard real-time system,”inProc. IEEE Real-Time Syst. Symp., 1987, pp. 261–270.
[11] C.L. Liu and J.W. Layland, “Scheduling Algorithms for Multiprogramming in a Hard Real-Time Environment,” J. ACM, vol. 20, no. 1, pp. 40-61, 1973.
[12] Y. Lin and S.H. Son, “Concurrency Control in Real-Time Databases by Dynamic Adjustment of Serialization Order,” Proc. IEEE 11th Real-Time Systems Symp., Dec. 1990.
[13] A. K. Mok,“The design of real time programming systems based on process models,”inProc. IEEE Real-Time Syst. Symp., Dec. 1984, pp. 5–16.
[14] J. F. Ready,“VRTX: A real-time operating system for embedded microprocessor applications,”IEEE Micro, vol. 4, no. 6, pp. 8–17, June 1986.
[15] J.H. Saltzer, D.P. Reed, and D.D. Clark, "End-to-End Arguments in System Design," ACM Trans. Computer Systems, vol. 2, no. 4, Nov. 1984, pp. 277-288.
[16] D. Sleator and R. Tarjan, “Amortized Efficiency of List Update and Paging Rules,” Comm. ACM, vol. 28, no. 2, pp. 202–208, 1985.
[17] B. Sprunt, L. Sha, and J. Lehoczky,“Aperiodic task scheduling for hard-real-time systems,”The J. Real-Time Syst., vol. 1, pp. 27–60, 1989.
[18] L. Tein-Hsiang and W. Tarng,“Scheduling periodic and aperiodic tasks in hard real-time computing systems,”Perform. Eval. Rev., vol. 19, no. 1, pp. 31–38, May 1991.
[19] W. Zhao and J. A. Stankovic,“Performance analysis of FCFS and improved FCFS scheduling algorithms for dynamic real-time computer systems,”inProc. IEEE Real-Time Syst. Symp., Dec. 1989, pp. 156–165.

Citation:
Stefan Poledna, "Tolerating Sensor Timing Faults in Highly Responsive Hard Real-Time Systems," IEEE Transactions on Computers, vol. 44, no. 2, pp. 181-191, Feb. 1995, doi:10.1109/12.364530
Usage of this product signifies your acceptance of the Terms of Use.