Program Execution Time, Reliability and Queueing Analysis in

This term paper contains three main chapters. The first one is the analysis for program execution times with various checkpointing strategies; the second one is the expected-reliability analysis; and the last one is queueing analysis for message sojourn time in Access Bridge. All these analysis are conducted in mobile environments which is demonstrated by Wireless CORBA. We employ the number of received computational messages instead of time to indicate the completion of pro-gram execution on a mobile host. Handoff is another distinct factor that should be taken into consideration in mobile environments. Two checkpointing strategies, deterministic and random checkpointing, are investigated. In our approach, failures may occur during checkpointing and recovery periods. We derive the Laplace-Stieltjes Transform of the cumulative distribution function of the program execution time and its expectation. We propose a new term, two-terminal expected-reliability, to integrate different communication structures, which is introduced by handoff and therefore is unique in mobile environments, into one metric. The two-terminal expected-reliability includes not only the failure parameters but also the service parameters. Nevertheless, it is still a monotonically decreasing function of time We study five message dispatch models in Access Bridges, which are basic queueing model, static and dynami