Published online by Cambridge University Press: 27 July 2009
We consider a problem in which jobs continually arrive to a set of n processors that are arranged in an ordered list. When a job arrives the first processor in line attempts to process it; if it is unsuccessful then the next in line attempts it, and so on. Each time that processor j attempts to process a job it is, independently of all else, successful with (an unknown) probability pj. After a job has been completed or all n attempts have failed then, based on the result, we can reorder the processors before the next job arrives, with the objective being to minimize the average number of attempts per job. This paper compares the transposition rule and the move to the front rule.