1. A method of fulfilling a request to perform a task, the request being made available to a set of worker computers, each worker computer of the set of worker computers being constructed and arranged to perform tasks corresponding to particular requests in a first queue within a first wait period, the method comprising: placing the request in the first queue and placing a copy of the request in a second queue; if the copy of the request is not found in the second queue after a second wait period which is smaller than the first wait period, monitoring progress of the performance of the task; and if the copy of the request is found in the second queue after the second wait period, sending a message to a client computer, the message informing the client computer that the set of worker computers is currently unable to perform the task within the first wait period.