1. A method in a computing system for executing a multithreaded program, comprising: for each of a plurality of machines, causing the machine to execute the multithreaded program deterministically, the deterministic execution comprising receiving one or more inputs, such that the deterministic execution of the multithreaded program is replicated across the plurality of machines; detecting a problem in the execution of the multithreaded program by one of the plurality of machines; and in response to the detecting, disabling the operation of the machine in whose execution of the multithreaded program the problem was detected, wherein the disabling comprises preventing the receipt of further inputs by the machine in whose execution of the multithreaded program the problem was detected.