How are the number of active machines calculated?
One central problem in distributed computing is the calculation of how many computers are actively part of the project. Many projects merely cite the “total number of devices”, i.e. the number of computers to ever be a part of the calculation. This can of course grossly overestimate the current power of the distributed computing network. Instead, we calculate the number of “active” clients, i.e. machines that have returned work recently. Active PS3’s are defined as those which have returned WUs within the last 2 days. This is a much shorter timeout than what we set for normal CPU clients, as the PS3 client’s WU deadline is much shorter (typically 2 days). However, as we communicate with the distributed clients fairly infrequently (no more frequently than every 8 hours), it is hard to precisely know how many machines are running and these numbers are best used as an order of magnitude estimate of the power of our network.
