Patent ID: 7107337

Claim:
A network adapter that may be used in a network data storage system to permit data communication among data exchanging devices and a data storage system input/output (I/O) controller, the controller residing in the data storage system, the data exchanging devices being external to the adapter, the adapter comprising: one or more interfaces that may be coupled to an electrical backplane of the system, the backplane being coupled to the controller and being configured to permit communication between the controller and the adapter when the one or more interfaces are coupled to the backplane; and a switching system integrated into the adapter, the switching system having a first set of ports that may be coupled to the data exchanging devices and a second set of ports that may couple the switching system to the controller when the one or more interfaces are coupled to the backplane, wherein the switching system is configured to selectively provide one of (i) communications between the controller and the data exchanging devices through the first and second sets of ports, and (ii) a test loop which loops the second set of ports back to the controller to enable the controller to diagnostically test controller operation and connectivity between the controller and the adapter through the backplane using a set of test vectors through the second set of ports; wherein the switching system is further configured to isolate the controller from the data exchanging devices to avoid escape of signals from the controller to the data exchanging devices when the switching system selectively provides the test loop; wherein the controller is a single circuit board having multiple Fibre Channel interfaces, and wherein the switching system is configured to daisy chain the multiple Fibre Channel interfaces of the single circuit board together exclusive of the data exchanging devices when the switching system selectively provides the test loop; wherein the adapter is a host bus adapter device which interconnects between a host node and the controller, the controller being configured to operate as a front-end interface between the host node and a cache of the data storage system; and wherein the adapter further comprises: control circuitry coupled to the one or more interfaces and further coupled to the switching system, the control circuitry being configured to perform host bus adapter operations to move data between the host node and the cache when the switching system is not selectively providing the test loop, the host bus adapter operations being different than disk adapter operations for moving data between the cache and the data exchanging devices.