Server and method of recovery from link failure in server

In a server composed of a server module having a processor in it, an I/O module having an I/O extension slot for accommodating an I/O extension adapter to expand the server's I/O capability, and a management module managing the entire server, the server module and the I/O extension slot (and through it, ultimately the I/O extension adapter) are interconnected using a PCI Express interface and the I/O module and the management module are interconnected using a special interface carrying detection information indicating whether an I/O extension adapter is actually mounted on the I/O extension slot. In the event of a link failure on the PCI Express interface, link recovery is attempted by grasping the status of the link based on the detection information obtained through the special interface.