A soft real time scheduling server in UNIX operating system

  • Hao-hua Chu
  • Klara Nahrstedt
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1309)


We present a soft real-time CPU server for Continuous Media processing in the UNIX environment. The server is a daemon process from which applications can request and acquire soft real-time QoS (Quality of Service) Guarantees. Our server architecture addresses in addition to other multimedia CPU scheduling extensions properties such as fairness, QoS brokerage and enforcement, and security. Overall it provides (1) protection among real-time(RT) processes, (2) fairness among RT and non-RT processes, (3) rate monotonic scheduling, and (4) a fix to the UNIX security problem. We have implemented our soft real-time CPU server in the SUN Solaris 2.5 Operating System, and we have shown through experiments that our soft RT server provides predictable QoS for continuous media applications.


Server Architecture Schedulability Test Page Fault Dynamic Priority UNIX Environment 
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  1. 1.
    Chen Lee, Ragunathan Rajkumar, and Cliff Mercer. “Experience with Processor Reservation and Dynamic QOS in Real-Time Mach”. Multimedia Japan, 1996.Google Scholar
  2. 2.
    Pawan Goyal, Xingang Guo, and Harrick Vin. “A Hierarchical CPU Scheduler for Multimedia Operating System”. The proceedings of Second Usenix Symposium on Operating System Design and Implementation.Google Scholar
  3. 3.
    Bill O. Gallmeister. “Programming for the Real World: POSIX.4”. O'Reilly & Associates, INC. 1995.Google Scholar
  4. 4.
    Clifford W. Mercer, Stefan Savage, and Hideyuki Tokuda. “Processor Capacity Reserves: Operating System Support for Multimedia Applications”. IEEE International Conference on Multimedia Computing and Systems. May 1994.Google Scholar
  5. 5.
    Jason Nieh, James G. Hanko, J. Duane Northcutt, and Gerard A. Wall. “SVR4 UNIX Scheduler Unacceptable for Multimedia Applications”. Fourth International Workshop on Network and Operating System Support for Digital Audio and Video. Nov 1993.Google Scholar
  6. 6.
    Jun Kamada, Masanobu Yuhara, Etsuo Ono. “User-level Realtime Scheduler Exploiting Kernel-level Fixed Priority Scheduler”. Multimedia Japan, March 1996.Google Scholar
  7. 7.
    Sandeep Khana, Michael Sebree, and John Zolnowsky. “Realtime Scheduling in SunOS 5.0”. USENIX Winter 1992 Technical Conference.Google Scholar
  8. 8.
    David K.Y. Yau and Simon S. Lam. “Adaptive Rate-Controlled Scheduling for Multimedia Applications”. ACM Multimedia Conference '96, Boston, MA, Nov 1996.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Hao-hua Chu
    • 1
  • Klara Nahrstedt
    • 1
  1. 1.University of Illinois at Urbana ChampaignUrbanaUSA

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