Abstract: One or more combinations of an operating data processing machine and a backup data processing machine are connected together to enable backup switching wherein the backup machine takes over the data processing from the operating machine when a failure occurs in the operating machine. In particular, each of the operating and backup machines is connected to one or several system resources, such as data storage or data output devices. The operating processor exclusively occupies the system resources, and when a failure occurs the operating processor is disconnected therefrom. A disconnection completion notice is sent to the backup processor, which then begins to exclusively occupy the system resources for performing ongoing data processing that would have been performed by the operating processor had the failure not occurred. When a failure occurs with the operating processor, the data being processed and the data concerning the failure are dumped to an auxiliary memory to facilitate analysis of the failure.