1. A method of scheduling processing jobs on processing entities, the method comprising the steps of: receiving real-time reliability data associated with a processing entity; generating a reliability score for the processing entity based on at least some of the received reliability data and based on a prior reliability score for the processing entity; receiving a processing job for scheduling, the processing job having associated with it a minimum acceptable reliability score; and scheduling the received processing job on the processing entity only if the generated reliability score is greater than or equal to the minimum acceptable reliability score associated with the processing job.