Collecting unused processing capacity: an analysis of transient distributed systems

Distributed systems having large numbers of idle computers and workstations are analyzed using a very simple model of a distributed program (a fixed amount of work) to see how the use of transient processors affects the program's service time. The probability density of the length of time it takes to finish a fixed amount of work is determined. An equation is given for the main result for an M-processor network. Simulations confirm that Brownian motion with drift is an accurate model of system performance. With large programs that run for a long time relative to the length of available and nonavailable periods, the central limit-theorem applies, and the Brownian-motion-with-drift model remains good regardless of the distributions of the available and the nonavailable periods. Under these assumptions, the distribution of finishing time is very tight about its mean and well approximated by a normal distribution.<>