A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform operations for a subscribing computer to participate in an aggregate computing task, where the subscribing computer has a principal function distinct from the aggregate computing task, the method being performed by a subscribing computer and comprising:
- in response to an announcement of an opportunity for computers to participate in an aggregate computing task, submitting a request to participate in the subscribing aggregate computing task;
- receiving from the coordinating computer at least one of multiple independent subtasks of an aggregate computing task, and also receiving an idle time activation program;
- installing the idle time activation program, whereupon the idle time activation program causes the subscribing computer to perform operations including working toward completion of the assigned subtask when the subscribing computer is in a predefined idle state with respect to the subscribing computer's principal functions, and halting work toward completion of the assigned subtask during periods when the subscribing computer is not in the predefined idle state;
- and
- in response to the completion of the received subtask, transmitting results of the subtask to the coordinating computer.