International Business Machines Corporation

Steven W Thurber

Renato John Recio

Douglas Morgan Freimuth

William Gavin Holland

William Todd Boyd

Madeline Vega

Steven Wade Hunter

In a distributed computer system having multiple root nodes, a challenge protocol is provided, for use in determining or confirming the root node in which a PCI Configuration Manager (PCM) actually resides. This node is referred to as the master node. The challenge procedure is activated whenever the identity of the PCM, which is determined by the root node in which it resides, appears to be uncertain. The challenge procedure resolves this uncertainty, and enables the PCM to continue to configure routings throughout the system. In a useful embodiment, a method is directed to a distributed computer system of the above type which is further provided with PCI switches and with adapters that are available for sharing by different nodes. The method includes the steps of selecting a first one of the root nodes to be master root node, and operating the first root node to query the configuration space of a particular one of the PCI switches. The method further includes detecting information indicating that a second root node is considered to be the master root node for the particular switch. A challenge protocol is implemented in response to this detected information, to seek confirmation that the first root node is the master root node. The configuration space querying procedure is continued if the first root node is confirmed to be the master root node, and is otherwise aborted.

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Austin, TX, United States of America

Steven W Thurber