Patent ID: 7137124

Claim:
In a storage area network (SAN) comprising one or more digital data processors in communication with one or more storage devices, wherein at least a selected one of the digital data processors operates under an operating system having a port driver defining a software interface between a class driver and an adapter to which one or more of the storage devices are coupled, the class driver for claiming one or more of the storage devices for access by the operating system and any application programs executing therein by invoking the port driver to which the selected digital data processor is coupled, the improvement comprising: a filter in communication with the port driver and the class driver, the filter intervening to block claiming of one or more of the storage devices by the class driver, the class driver issuing a claim request to the port driver for a selected one of the storage devices, the port driver issuing a response to the class driver, the filter intercepting the response from the port driver, determining whether the selected storage device has been assigned to the selected digital data processor, and, in response to determining that the storage device has not been assigned, blocking claiming of the selected storage device.