A memory hub includes an on-board diagnostic engine through which diagnostic testing and evaluation of the memory system can be performed. The memory hub includes a link interface for receiving memory requests for access to memory devices of the memory system and a memory device interface coupled to the memory devices for coupling memory requests to the memory devices. A memory hub diagnostic engine is coupled through a switch to the link interface and the memory device interface to perform diagnostic testing of the memory system. The diagnostic engine includes a maintenance port that provides access to results of the diagnostic testing and through which diagnostic testing commands can be received.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 11/433,130, filed May 11, 2006, issued as U.S. Pat. No. 7,278,060, which is a continuation of U.S. patent application Ser. No. 10/644,522, filed Aug. 19, 2003, issued Apr. 24, 2007 as U.S. Pat. No. 7,210,059 B2.
