A method and apparatus for testing the transmitter and receiver links of an I/O node. A test mode in an I/O node is initiated by a test signal driven from a test system to the I/O node via a loadboard. The I/O node may then receive test data through a peripheral bus interface. The inputting may be performed synchronously to a first clock signal. The I/O node may then transmit the test data to a receiver via a loopback mechanism on the loadboard. The transmission and reception of test data between transmitter and receiver is synchronous to a second clock signal, which has a frequency equal to the operational frequency of the transmitter and receiver. The receiver may forward the test data to the peripheral bus interface, which may in turn output the test data to the test system. The test system may then determine the results of the test.
A data storage system includes a plurality of disk drives for data storage. A storage server controls the reading and writing of data to the disk drives. The storage server can be tested prior to connecting the disk drives and other components of the data storage system by connecting ports of the storage server to other ports of the storage server. One of the connected ports is changed from an initiator to a target to simulate a the target state of a disk drive. The server can test itself at normal data transfer rates using the initiator-target pair just as if it was testing a normal server/disk drive connection, but without having to test the actual disk drive and without having to detect or distinguish any problems that may exist with the disk drive and its connection, or other components that may be in the loop.
