Anytime System Scheduler for Insufficient Resource Availability
Annamária R. Várkonyi-Kóczy, and Gábor Samu
Department of Measurement and Information Systems, Integrated Intelligent Systems Japanese-Hungarian Joint Laboratory, Budapest University of Technology and Economics, H-1521, Magyar Tudósok krt. 2., Hungary
Anytime systems are advantageous when resource and/or data availability changes during operation and some kind of intelligent reconfiguration of the system is needed to cope with temporal data and resource access conditions. Such systems may provide an optimal tradeoff between time/resource needs and computational complexity and the quality (accuracy) of results and are designed using special models, methods, and algorithms together with applying active monitoring for being able to supervise the operation of the system on-line and making intelligent decisions based on sensory information of so-called shortage indicators. Since the monitor operates under prescribed response time requirements and the number and complexity of the executable tasks may be very high, especially in complex systems, new considerations must constantly be made to achieve optimal or acceptable performance. In software terms, this requires the application of special compilation methods dealing also with timing considerations and constraints of the underlying operating system and even with the run-time characteristics of the monitor. This must also be supported by anytime development tools and special anytime description languages. In this paper a hierarchical compilation method is introduced together with theoretical considerations about a possible anytime development tool and the basics of the anytime description meta-language ATDL are presented.