Pierre M. Fiorini

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For many systems, failure is so common that the design choice of how to deal with it may have a significant impact on the performance of the system. There are many specific and distinct failure recovery schemes, but they can be grouped into three broad classes: <i>RESUME</i>, also referred to as preemptive resume (prs), or check-pointing; <i>REPLACE</i>,(More)
Many processes must complete in the presence of failures. Different systems respond to task failure in different ways. The system may resume a failed task from the failure point (or a saved checkpoint shortly before the failure point), it may give up on the task and select a replacement task from the ready queue, or it may restart the task. The behavior of(More)
For some computing systems, failure is rare enough that it can be ignored. In other systems, failure is so common that how to handle it can have a significant impact on the performance of the system. There are many different recovery schemes for tasks, however, they can be classified into three broad categories: 1) <i>Resume:</i> when a task fails, it knows(More)
1 A short review of what we call \Linear Algebraic Queueing Theory (LAQT)" is presented, including the basic formulas for matrix representations of Phase (or`Matrix Exponential') Distributions. Semi-Markov (or Markov Renewal) Processes are then described in this formulation, with particular emphasis on`Markov Modulated Poisson Processes (MMPP).' The MMPP(More)
In an E-commerce it is important to ensure performance of the system is satisfactory-especially during peak hour(s). To meet service level objectives then at least three functions must be performed: 1) Identify critical system performance metrics (CSM's); 2) Determine via analytic techniques or qualitative analysis " thresholds " for performance metrics(More)